14
14
Jun 25, 2018
06/18
by
B. M. Gaensler; Iván Agudo; Takuya Akahori; Julie Banfield; Rainer Beck; Ettore Carretti; Jamie Farnes; Marijke Haverkorn; George Heald; David Jones; Thomas Landecker; Sui Ann Mao; Ray Norris; Shane O'Sullivan; Lawrence Rudnick; Dominic Schnitzeler; Nicholas Seymour; Xiaohui Sun
texts
eye 14
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Faraday rotation of polarised background sources is a unique probe of astrophysical magnetic fields in a diverse range of foreground objects. However, to understand the properties of the polarised sources themselves and of depolarising phenomena along the line of sight, we need to complement Faraday rotation data with polarisation observations over very broad bandwidths. Just as it is impossible to properly image a complex source with limited u-v coverage, we can only meaningfully understand...
Topics: Cosmology and Nongalactic Astrophysics, Astrophysics, Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1501.00626
32
32
Jun 25, 2018
06/18
by
R. Buta; K. Sheth; E. Athanassoula; A. Bosma; J. Knapen; E. Laurikainen; H. Salo; D. Elmegreen; L. Ho; D. Zaritsky; H. Courtois; J. Hinz; J-C. Muñoz-Mateos; T. Kim; M. Regan; D. Gadotti; A. Gil de Paz; J. Laine; K. Menendez-Delmestre; Sebastien Comeron; S. Erroz Ferrer; M. Seibert; T. Mizusawa; B. Holwerda; B. Madore
texts
eye 32
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The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest available database of deep, homogeneous middle-infrared (mid-IR) images of galaxies of all types. The survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications of S4G galaxies in the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. The CVRHS system follows the precepts of classical de...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00454
32
32
Jun 25, 2018
06/18
by
Gabriele Giovannini; Annalisa Bonafede; Shea Brown; Luigina Feretti; Chiara Ferrari; Myriam Gitti; Federica Govoni; Matteo Murgia; Valentina Vacca
texts
eye 32
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The presence of magnetic fields in galaxy clusters has been well established in recent years, and their importance for the understanding of the physical processes at work in the Intra Cluster Medium has been recognized. Halo and relic sources have been detected in several tens clusters. A strong correlation is present between the halo and relic radio power and the X-ray luminosity. Since cluster X-Ray luminosity and mass are related, the correlation between the radio power and X-ray luminosity...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.01023
11
11
Jun 25, 2018
06/18
by
Shaohua Zhang; Hongyan Zhou; Tinggui Wang; Huiyuan Wang; Xiheng Shi; Bo Liu; Wenjuan Liu; Zhenzhen Li; Shufen Wang
texts
eye 11
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We present the variability study of broad absorption lines (BALs) in a uniformly radio-selected sample of 28 BAL quasars using the archival data from the FIRST Bright Quasar Survey (FBQS) and the Sloan Digital Sky Survey (SDSS), as well as those obtained by ourselves, covering time scales $\sim 1-10$ years in the quasar's rest-frame. To our surprise, 5 quasars showing strong variations are all belong to a special subclass of overlapping iron low ionization BAL (OFeLoBAL) quasars, however, other...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00091
26
26
Jun 25, 2018
06/18
by
Manda Banerji; S. Alaghband-Zadeh; Paul C. Hewett; Richard G. McMahon
texts
eye 26
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We present a new population of z>2 dust-reddened, Type 1 quasars with 0.510^{13}L_0), high-redshift dusty quasars to 38. There is no evidence for reddened quasars having significantly different H$\alpha$ equivalent widths relative to unobscured quasars. The average black-hole masses (~10^9-10^10 M_0) and bolometric luminosities (~10^{47} erg/s) are comparable to the most luminous unobscured quasars at the same redshift, but with a tail extending to very high luminosities of ~10^{48} erg/s....
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00815
10
10.0
Jun 25, 2018
06/18
by
R. E. A. Canning; G. J. Ferland; A. C. Fabian; R. M. Johnstone; P. A. M. van Hoof; R. L. Porter; N. Werner; R. J. R. Williams
texts
eye 10
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Many massive galaxies at the centres of relaxed galaxy clusters and groups have vast reservoirs of cool (~10,000 K) and cold (~100 K) gas. In many low redshift brightest group and cluster galaxies this gas is lifted into the hot ISM in filamentary structures, which are long lived and are typically not forming stars. Two important questions are how far do these reservoirs cool and if cold gas is abundant what is the cause of the low star formation efficiency? Heating and excitation of the...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.01081
20
20
Jun 25, 2018
06/18
by
F. de Gasperin; G. A. Ogrean; R. J. van Weeren; W. A. Dawson; M. Brüggen; A. Bonafede; A. Simionescu
texts
eye 20
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Extended steep-spectrum radio emission in a galaxy cluster is usually associated with a recent merger. However, given the complex scenario of galaxy cluster mergers, many of the discovered sources hardly fit into the strict boundaries of a precise taxonomy. This is especially true for radio phoenixes that do not have very well defined observational criteria. Radio phoenixes are aged radio galaxy lobes whose emission is reactivated by compression or other mechanisms. Here, we present the...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00043
17
17
Jun 25, 2018
06/18
by
A. Popping; M. Meyer; L. Staveley-Smith; D. Obreschkow; G. I. Jozsa; D. J. Pisano
texts
eye 17
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The interaction of galaxies with their environment, the Intergalactic Medium (IGM), is an important aspect of galaxy formation. One of the most fundamental, but unanswered questions in the evolution of galaxies is how gas circulates in and around galaxies and how it enters the galaxies to support star formation. We have several lines of evidence that the observed evolution of star formation requires gas accretion from the IGM at all times and on all cosmic scales. This gas remains largely...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.01077
81
81
Jun 25, 2018
06/18
by
Shadab Alam; Franco D. Albareti; Carlos Allende Prieto; F. Anders; Scott F. Anderson; Brett H. Andrews; Eric Armengaud; Éric Aubourg; Stephen Bailey; Julian E. Bautista; Rachael L. Beaton; Joseph Huehnerhoff; Linhua Jiang; Jennifer A. Johnson; Karen Kinemuchi; David Kirkby; Francisco Kitaura; Mark A. Klaene; Jean-Paul Kneib; Xavier P. Koenig; Charles R. Lam; Timothy C. Beers; Ting-Wen Lan; Dustin Lang; Pierre Laurent; Jean-Marc Le Goff; Alexie Leauthaud; Khee-Gan Lee; Young Sun Lee; Timothy C....
texts
eye 81
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The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics, Astrophysics of Galaxies, Astrophysics,...
Source: http://arxiv.org/abs/1501.00963
22
22
Jun 25, 2018
06/18
by
Martin Meyer; Aaron Robotham; Danail Obreschkow; Simon Driver; Lister Staveley-Smith; Martin Zwaan
texts
eye 22
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The science achievable with SKA HI surveys will be greatly increased through the combination of HI data with that at other wavelengths. These multiwavelength datasets will enable studies to move beyond an understanding of HI gas in isolation to instead understand HI as an integral part of the highly complex baryonic processes that drive galaxy evolution. As they evolve, galaxies experience a host of environmental and feedback influences, many of which can radically impact their gas content....
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.01082
29
29
Jun 25, 2018
06/18
by
Hanno Rein
texts
eye 29
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The multi-planetary system HD128311 hosts at least two planets. Its dynamical formation history has been studied extensively in the literature. We reanalyse the latest radial velocity data for this system with the affine-invariant Markov chain Monte Carlo sampler EMCEE. Using the high order integrator IAS15, we perform a fully dynamical fit, allowing the planets to interact during the sampling process. A stability analysis using the MEGNO indicator reveals that the system is located in a stable...
Topics: Earth and Planetary Astrophysics, Astrophysics, Instrumentation and Methods for Astrophysics,...
Source: http://arxiv.org/abs/1501.00980
20
20
Jun 25, 2018
06/18
by
Jorge I. Zuluaga; Paul A. Mason; Pablo A. Cuartas
texts
eye 20
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The discovery of many planets using the Kepler telescope includes ten planets orbiting eight binary stars. Three binaries, Kepler-16, Kepler-47, and Kepler-453, have at least one planet in the circumbinary habitable-zone (BHZ). We constrain the level of high-energy radiation and the plasma environment in the BHZ of these systems. With this aim, BHZ limits in these Kepler binaries are calculated as a function of time, and the habitability lifetimes are estimated for hypothetical terrestrial...
Topics: Earth and Planetary Astrophysics, Astrophysics, Solar and Stellar Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00296
20
20
Jun 25, 2018
06/18
by
J. M. Stil; B. W. Keller
texts
eye 20
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Stacking polarized radio emission in SKA surveys provides statistical information on large samples that is not accessible otherwise due to limitations in sensitivity, source statistics in small fields, and averaging over frequency (including Faraday synthesis). Polarization is a special case because one obvious source of stacking targets is the Stokes I source catalog, possibly in combination with external catalogs, for example an SKA HI survey or a non-radio survey. We point out the...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics, Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1501.00390
26
26
Jun 25, 2018
06/18
by
J. Singal; A. Kogut; E. Jones; H. Dunlap
texts
eye 26
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We use surface brightness contour maps of nearby edge-on spiral galaxies to determine whether extended bright radio halos are common. In particular, we test a recent model of the spatial structure of the diffuse radio continuum by Subrahmanyan and Cowsik which posits that a substantial fraction of the observed high-latitude surface brightness originates from an extended Galactic halo of uniform emissivity. Measurements of the axial ratio of emission contours within a sample of normal spiral...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00499
17
17
Jun 25, 2018
06/18
by
Hannah Jang-Condell
texts
eye 17
favorite 0
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To date, several exoplanets have been discovered orbiting stars with close binary companions (a~
Topics: Earth and Planetary Astrophysics, Astrophysics, Solar and Stellar Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1501.00617
31
31
Jun 25, 2018
06/18
by
Ivan Agudo; Markus Boettcher; Heino Falcke; Markos Georganopoulos; Gabriele Ghisellini; Gabriele Giovannini; Marcello Giroletti; Jose L. Gomez; Leonid Gurvits; Robert Laing; Matthew Lister; Jose-Maria Marti; Eileen T. Meyer; Yosuke Mizuno; Shane O'Sullivan; Paolo Padovani; Zsolt Paragi; Manel Perucho; Dominik Schleicher; Lukasz Stawarz; Nektarios Vlahakis; John Wardle
texts
eye 31
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Relativistic jets in active galactic nuclei (AGN) are among the most powerful astrophysical objects discovered to date. Indeed, jetted AGN studies have been considered a prominent science case for SKA, and were included in several different chapters of the previous SKA Science Book (Carilli & Rawlings 2004). Most of the fundamental questions about the physics of relativistic jets still remain unanswered, and await high-sensitivity radio instruments such as SKA to solve them. These questions...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics, High...
Source: http://arxiv.org/abs/1501.00420
6
6.0
Jun 30, 2018
06/18
by
Michael Burton; Michael Ashley; Catherine Braiding; John Storey; Craig Kulesa; David Hollenbach; Mark Wolfire; Christian Glueck; Gavin Rowell
texts
eye 6
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We present spectral line images of [CI] 809 GHz, CO J=1-0 115 GHz and HI 1.4 GHz line emission, and calculate the corresponding C, CO and H column densities, for a sinuous, quiescent Giant Molecular Cloud about 5 kpc distant along the l=328{\deg} sightline (hereafter G328) in our Galaxy. The [CI] data comes from the High Elevation Antarctic Terahertz (HEAT) telescope, a new facility on the summit of the Antarctic plateau where the precipitable water vapor falls to the lowest values found on the...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.0421
5
5.0
Jun 30, 2018
06/18
by
Yusuke Fujimoto; Elizabeth J. Tasker; Mariko Wakayama; Asao Habe
texts
eye 5
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We investigate the impact of galactic environment on the properties of simulated giant molecular clouds formed in a M83-type barred spiral galaxy. Our simulation uses a rotating stellar potential to create the grand design features and resolves down to 1.5 pc. From the comparison of clouds found in the bar, spiral and disc regions, we find that the typical GMC is environment independent, with a mass of 5e+5 Msun and radius 11 pc. However, the fraction of clouds in the property distribution...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.1212
7
7.0
Jun 30, 2018
06/18
by
J. Wagg; C. L. Carilli; M. Aravena; P. Cox; L. Lentati; R. Maiolino; R. G. McMahon; D. Riechers; F. Walter; P. Andreani; R. Hills; A. Wolfe
texts
eye 7
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We present Karl G. Jansky Very Large Array (VLA) observations of 44 GHz continuum and CO J=2-1 line emission in BR1202-0725 at z=4.7 (a starburst galaxy and quasar pair) and BRI1335-0417 at z=4.4 (also hosting a quasar). With the full 8 GHz bandwidth capabilities of the upgraded VLA, we study the (rest-frame) 250 GHz thermal dust continuum emission for the first time along with the cold molecular gas traced by the Low-J CO line emission. The measured CO J=2-1 line luminosities of BR1202-0725...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.1213
3
3.0
Jun 30, 2018
06/18
by
Owain N. Snaith; Misha Haywood; Paola Di Matteo; Matthew D. Lehnert; Francoise Combes; David Katz; Ana Gomez
texts
eye 3
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We report the first robust measurement of the Milky Way star formation history using the imprint left on chemical abundances of long-lived stars. The formation of the Galactic thick disc occurs during an intense star formation phase between 9.0 (z~1.5) and 12.5 Gyr (z~4.5) ago and is followed by a dip (at z~1.1) lasting about 1 Gyr. Our results imply that the thick disc is as massive as the Milky Way's thin disc, suggesting a fundamental role of this component in the genesis of our Galaxy,...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.1835
5
5.0
Jun 30, 2018
06/18
by
Daniel Ruschel-Dutra; Miriani Pastoriza; Rogério Riffel; Dinalva A. Sales; Cláudia Winge
texts
eye 5
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New Gemini mid-infrared spectroscopic observations together with Spitzer Space telescope archival data, are used to study the properties of the dusty torus and circumnuclear star formation in the active galaxies NGC 7213 and NGC 1386. Our main conclusions can be summarised as follows. Polycyclic aromatic hydrocarbon (PAH) emission is absent in the T-ReCS nuclear spectra but is ubiquitous in the data from Spitzer at distances above 100 pc. Star formation rates surface densities are estimated...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.1989
9
9.0
Jun 30, 2018
06/18
by
N. R. Crockett; E. A. Bergin; J. L. Neill; J. H. Black; G. A. Blake; M. Kleshcheva
texts
eye 9
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We present Herschel/HIFI observations of the light hydride H$_{2}$S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the HEXOS GT key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H$_{2}$$^{32}$S, H$_{2}$$^{34}$S, and H$_{2}$$^{33}$S, respectively. We only analyze emission from the so called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.2470
3
3.0
Jun 30, 2018
06/18
by
S. Karaali; S. Bilir; S. Ak; E. Yaz Gokce; O. Onal; T. Ak
texts
eye 3
favorite 0
comment 0
We investigated the space velocity components of 6610 red clump (RC) stars in terms of vertical distance, Galactocentric radial distance and Galactic longitude. Stellar velocity vectors are corrected for differential rotation of the Galaxy which is taken into account using photometric distances of RC stars. The space velocity components estimated for the sample stars above and below the Galactic plane are compatible only for the space velocity component in the direction to the Galactic rotation...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.2601
8
8.0
Jun 30, 2018
06/18
by
J. B. R. Oonk; R. J. van Weeren; F. Salgado; L. K. Morabito; A. G. G. M. Tielens; H. J. A. Rottgering; A. Asgekar; G. J. White; A. Alexov; J. Anderson; I. M. Avruch; S. Yatawatta; P. Zarka; A. Zensus; F. Batejat; R. Beck; M. E. Bell; I. van Bemmel; M. J. Bentum; G. Bernardi; P. Best; A. Bonafede; F. Breitling; M. Brentjens; J. Broderick; M. Brueggen; H. R. Butcher; B. Ciardi; J. E. Conway; A. Corstanje; F. de Gasperin; E. de Geus; M. de Vos; S. Duscha; J. Eisloeffel; D. Engels; J. van Enst; H....
texts
eye 8
favorite 0
comment 0
We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the LOw Frequency ARray in the 33 to 57 MHz range. These low frequency radio observations provide us with a new line of sight to study the diffuse, neutral gas in our Galaxy. To our knowledge this is the first time that foreground Milky Way recombination line absorption has been observed against a bright extragalactic background source. By...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.2876
3
3.0
Jun 30, 2018
06/18
by
B. Mookerjea; C. Vastel; G. E. Hassel; M. Gerin; J. Pety; P. F. Goldsmith; J. H. Black; T. Giesen; T. Harrison; C. M. Persson; J. Stutzki
texts
eye 3
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comment 0
In the framework of the Herschel/PRISMAS Guaranteed Time Key Program, the line of sight to the distant ultracompact HII region W51e2 has been observed using several selected molecular species. Most of the detected absorption features are not associated with the background high-mass star-forming region and probe the diffuse matter along the line of sight. We present here the detection of an additional narrow absorption feature at ~70 km/s in the observed spectra of HDO, NH3 and C3. The 70 km/s...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.0121
3
3.0
Jun 30, 2018
06/18
by
J. M. Stil; B. W. Keller; S. J. George; A. R. Taylor
texts
eye 3
favorite 0
comment 0
We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of a class of radio sources, but also avoids a detection threshold in polarized intensity, and therefore an arbitrary exclusion of source with a low percentage of polarization. Correction for polarization bias is done through a Monte Carlo analysis and tested on...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.1859
3
3.0
Jun 30, 2018
06/18
by
E. Roueff; A. B. Alekseyev; J. Le Bourlot
texts
eye 3
favorite 0
comment 0
Aims. Following the recent detection of 36ArH+ in the Crab nebula spectrum, we have computed the photodissociation rate of ArH+ in order to constrain the physical processes at work in this environment. Methods. Photodissociation cross sections of ArH+ are computed in an ab initio approach including explicit account of spin-orbit coupling. Results. We report the photodissociation cross section of ArH+ as a function of wavelength. Photodissociation probabilities are derived for different...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.2051
6
6.0
Jun 30, 2018
06/18
by
Shuo-Wen Jin; Qiusheng Gu; Song Huang; Yong Shi; Long-Long Feng
texts
eye 6
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We have analyzed the distributions in the color-magnitude diagram (CMD) of a large sample of face-on galaxies to minimize the effect of dust extinctions on galaxy color. About 300 thousand galaxies with $log(a/b) < $ 0.2 and redshift $z < 0.2$ are selected from the SDSS DR7 catalog. Two methods are employed to investigate the distributions of galaxies in the CMD including 1-D Gaussian fitting to the distributions in individual magnitude bins and 2-D Gaussian mixture model (GMM) fitting to...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.2398
4
4.0
Jun 30, 2018
06/18
by
D. V. Bizyaev; S. J. Kautsch; A. V. Mosenkov; V. P. Reshetnikov; N. Ya. Sotnikova; N. V. Yablokova; R. W. Hillyer
texts
eye 4
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comment 0
We present a catalog of true edge-on disk galaxies automatically selected from the Seventh Data Release (DR7) of the Sloan Digital Sky Survey. A visual inspection of the $g$, $r$ and $i$ images of about 15000 galaxies allowed us to split the initial sample of edge-on galaxy candidates into 4768 (31.8% of the initial sample) genuine edge-on galaxies, 8350 (55.7%) non-edge-ons, and 1865 (12.5%) edge-on galaxies not suitable for simple automatic analysis because these objects show signs of...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.3072
3
3.0
Jun 30, 2018
06/18
by
M. A. DiPompeo; A. D. Myers; M. S. Brotherton; J. C. Runnoe; R. F. Green
texts
eye 3
favorite 0
comment 0
Quasar luminosity functions are a fundamental probe of the growth and evolution of supermassive black holes. Measuring the intrinsic luminosity function is difficult in practice, due to a multitude of observational and systematic effects. As sample sizes increase and measurement errors drop, characterizing the systematic effects is becoming more important. It is well known that the continuum emission from the accretion disk of quasars is anisotropic --- in part due to its disk-like structure...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.3151
3
3.0
Jun 30, 2018
06/18
by
F. De Paolis; V. G. Gurzadyan; A. A. Nucita; G. Ingrosso; A. L. Kashin; H. G. Khachatryan; S. Mirzoyan; E. Poghosian; Ph. Jetzer; A. Qadir; D. Vetrugno
texts
eye 3
favorite 0
comment 0
Planck's data acquired during the first 15.4 months of observations towards both the disk and halo of the M31 galaxy are analyzed. We confirm the existence of a temperature asymmetry, previously detected by using the 7-year WMAP data, along the direction of the M31 rotation, therefore indicative of a Doppler-induced effect. The asymmetry extends up to about 10 degrees (about 130 kpc) from the M31 center. We also investigate the recent issue raised in Rubin and Loeb (2014) about the kinetic...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.4162
5
5.0
Jun 30, 2018
06/18
by
Akram Hasani Zonoozi; Hosein Haghi; Andreas H. W. Kuepper; Holger Baumgardt; Matthias J. Frank; Pavel Kroupa
texts
eye 5
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comment 0
We use direct $N$-body calculations to study the evolution of the unusually extended outer halo globular cluster Palomar 4 (Pal~4) over its entire lifetime in order to reproduce its observed mass, half-light radius, velocity dispersion and mass function slope at different radii. We find that models evolving on circular orbits, and starting from a non-mass segregated, canonical initial mass function (IMF) can reproduce neither Pal 4's overall mass function slope nor the observed amount of mass...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1404.5969
7
7.0
Jun 30, 2018
06/18
by
Poul Alexander; Mark Gieles; Henny Lamers; Holger Baumgardt
texts
eye 7
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comment 0
We present a new version of the fast star cluster evolution code Evolve Me A Cluster of StarS (EMACSS). While previous versions of EMACSS reproduced clusters of single-mass stars, this version models clusters with an evolving stellar content. Stellar evolution dominates early evolution, and leads to: (1) reduction of the mean mass of stars due to the mass loss of high-mass stars; (2) expansion of the half-mass radius; (3) for (nearly) Roche Volume filling clusters, the induced escape of stars....
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.1086
6
6.0
Jun 30, 2018
06/18
by
WeiBin Shi; YanChun Liang; Xu Shao; XiaoWei Liu; Gang Zhao; Francois Hammer; Yong Zhang; Hector Flores; GuiPing Ruan; Li Zhou
texts
eye 6
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We select 947 star-forming galaxies from SDSS-DR7 with [O~{\sc iii}]$\lambda$4363 emission lines detected at a signal-to-noise {ratio }larger than 5$\sigma$. Their electron temperatures and direct oxygen abundances are {then }determined. {W}e compare the results from different methods. $t_2${, the} electron temperature in {the }low ionization region{,} estimated from $t_3${, that} in {the }high ionization region{,} {is} compared {using} three analysis relations between $t_2-t_3${. These} show...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.1137
3
3.0
Jun 30, 2018
06/18
by
C. M. Brunt; C. Federrath
texts
eye 3
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comment 0
We introduce a new method for observationally estimating the fraction of momentum density (${\rho}{\mathbf{v}}$) power contained in solenoidal modes (for which $\nabla \cdot {\rho}{\mathbf{v}} = 0$) in molecular clouds. The method is successfully tested with numerical simulations of supersonic turbulence that produce the full range of possible solenoidal/compressible fractions. At present the method assumes statistical isotropy, and does not account for anisotropies caused by (e.g.) magnetic...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.1285
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4.0
Jun 30, 2018
06/18
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S. Hickinbottom; C. J. Simpson; P. A. James; E. Ibar; D. Carter; A. Boselli; C. A. Collins; J. I. Davies; L. Dunne; S. Eales; C. Fuller; B. Mobasher; R. F. Peletier; S. Phillipps; D. J. B. Smith; R. J. Smith; E. A. Valentijn
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We present new deep images of the Coma Cluster from the ESA Herschel Space Observatory at wavelengths of 70, 100 and 160 microns, covering an area of 1.75 x 1.0 square degrees encompassing the core and southwest infall region. Our data display an excess of sources at flux densities above 100 mJy compared to blank-field surveys, as expected. We use extensive optical spectroscopy of this region to identify cluster members and hence produce cluster luminosity functions in all three photometric...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.1598
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7.0
Jun 30, 2018
06/18
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M. Schultheis; G. Zasowski; C. Allende Prieto; F. Anders; R. L. Beaton; T. C. Beers; D. Bizyaev; C. Chiappini; P. M. Frinchaboy; A. E. Garcia-Perez; J. Ge; F. Hearty; J. Holtzman; S. R. Majewski; D. Muna; D. Nidever; M. Shetrone; D. P. Schneider
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Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily-reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.2180
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7.0
Jun 30, 2018
06/18
by
Michał J. Michałowski; Christopher C. Hayward; James S. Dunlop; Victoria A. Bruce; Michele Cirasuolo; Fergus Cullen; Lars Hernquist
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Submillimetre (submm) galaxies are among the most rapidly star-forming and most massive high-redshift galaxies; thus, their properties provide important constraints on galaxy evolution models. However, there is still a debate about their stellar masses and their nature in the context of the general galaxy population. To test the reliability of their stellar mass determinations, we used a sample of simulated submm galaxies for which we derived stellar masses via spectral energy distribution...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.2335
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3.0
Jun 30, 2018
06/18
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S. Salviander; G. A. Shields; E. W. Bonning
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We investigate the relationship between the mass of the central supermassive black hole, M_bh, and the host galaxy luminosity, L_gal, in a sample of quasars from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7). We use composite quasar spectra binned by black hole mass and redshift to assess galaxy features that would otherwise be overwhelmed by noise in individual spectra. The black hole mass is calculated using the photoionization method, and the host galaxy luminosity is inferred...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.2446
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4.0
Jun 30, 2018
06/18
by
Daniela Bettoni; Paola Mazzei; Roberto Rampazzo; Antonina Marino; Giuseppe Galletta; Lucio M. Buson
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The Galaxy Evolution Explorer (GALEX) detected ultraviolet emission in about 50% of multi-spin early-type galaxies (ETGs), suggesting the occurrence of a recent rejuvenation episode connected to the formation of these kinematical features. With the aim at investigating the complex evolutionary scenario leading to the formation of counter rotating ETGs (CR-ETGs) we use our Smooth Particle Hydrodynamic (SPH) code with chemo-photometric implementation. We discuss here the UV evolutionary path of...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.3873
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6.0
Jun 30, 2018
06/18
by
Nicolas Flagey; Alberto Noriega-Crespo; Andreea O. Petric; Tom R. Geballe
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eye 6
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We present near-IR spectroscopic observations of the central sources in 17 circumstellar shells from a sample of more than 400 "bubbles" discovered in the Spitzer/MIPSGAL 24um survey of the Galactic plane and in the Cyg-X region. To identify these shells, we have obtained J, H, and K band spectra with a resolution ~2600 of the stars at their centers. We observed 14 MIPSGAL bubbles (MBs), WR149, and 2 objects in the Cyg-X region (WR138a and BD+43 3710), our sample being about 2.5 mag...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.4023
3
3.0
Jun 30, 2018
06/18
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Joshua J. Adams; Joshua D. Simon; Maximilian H. Fabricius; Remco C. E. van den Bosch; John C. Barentine; Ralf Bender; Karl Gebhardt; Gary J. Hill; Jeremy D. Murphy; R. A. Swaters; Jens Thomas; Glenn van de Ven
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We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high resolution integral field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.4854
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4.0
Jun 30, 2018
06/18
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Edouard J. Bernard; Annette M. N. Ferguson; Edward F. Schlafly; Imants Platais; Eric F. Bell; Nicolas F. Martin; Hans-Walter Rix; Colin T. Slater; William S. Burgett; Kenneth C. Chambers; Peter W. Draper; Klaus W. Hodapp; Nicholas Kaiser; Rolf-Peter Kudritzki; Eugene A. Magnier; Nigel Metcalfe; John L. Tonry; Richard J. Wainscoat; Christopher Waters
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We present the fiducial sequences of a sample of Galactic star clusters in the five bands of the Pan-STARRS1 (PS1) photometric system (g_P1, r_P1, i_P1, z_P1, y_P1). These empirical sequences -- which include the red giant and sub-giant branches, the main sequence, and the horizontal branch -- were defined from deep colour-magnitude diagrams reaching below the oldest main-sequence turn-offs of 13 globular and 3 old open clusters covering a wide range of metallicities (-2.4 < [Fe/H] <...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.6644
3
3.0
Jun 30, 2018
06/18
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David C. Nicholls; Michael A. Dopita; Ralph S. Sutherland; Helmut Jerjen; Lisa J. Kewley; Hassan Basurah
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In this paper, we use the Mappings photoionization code to explore the physical parameters that impact on the measurement of electron temperature and abundance in HII regions. In the previous paper we presented observations and measurements of physical properties from the spectra of seventeen HII regions in fourteen isolated dwarf irregular galaxies from the SIGRID sample. Here, we analyze these observations further, together with three additional published data sets. We explore the effects of...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1405.7170
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4.0
Jun 30, 2018
06/18
by
Piero Madau; Daniel R. Weisz; Charlie Conroy
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On dwarf galaxy scales, the different shapes of the galaxy stellar mass function and the dark halo mass function require a star-formation efficiency (SFE) in these systems that is currently more than 1 dex lower than that of Milky Way-size halos. Here, we argue that this trend may actually be reversed at high redshift. Specifically, by combining the resolved star-formation histories of nearby isolated dwarfs with the simulated mass-growth rates of dark matter halos, we show that the assembly of...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1406.0838
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7.0
Jun 30, 2018
06/18
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S. P. Treviño-Morales; P. Pilleri; A. Fuente; C. Kramer; E. Roueff; M. González-García; J. Cernicharo; M. Gerin; J. R. Goicoechea; J. Pety; O. Berné; V. Ossenkopf; D. Ginard; S. García-Burillo; J. R. Rizzo; S. Viti
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The massive star-forming region Mon R2 hosts the closest ultra-compact HII region that can be spatially resolved with current single-dish telescopes. We used the IRAM-30m telescope to carry out an unbiased spectral survey toward two important positions (namely IF and MP2), in order to studying the chemistry of deuterated molecules toward Mon R2. We found a rich chemistry of deuterated species at both positions, with detections of C2D, DCN, DNC, DCO+, D2CO, HDCO, NH2D, and N2D+ and their...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1406.1373
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5.0
Jun 30, 2018
06/18
by
E. Laurikainen; H. Salo; E. Athanassoula; A. Bosma; M. Herrera-Endoqui
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Boxy/Peanut/X-shaped (B/P/X) bulges are studied using the 3.6 mum images from the Spitzer Survey of Stellar Structure in Galaxies, and the K_s-band images from the Near-IR S0 galaxy Survey. They are compared with the properties of barlenses, defined as lens-like structures embedded in bars, with sizes of about 50% of bars and axial ratios of 0.6-0.9. Based on observations and recent simulation models we show evidence that barlenses are the more face-on counterparts of B/P/X-shaped bulges. Using...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1406.1418
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4.0
Jun 30, 2018
06/18
by
Yuichi Harikane; Masami Ouchi; Suraphong Yuma; Michael Rauch; Kimihiko Nakajima; Yoshiaki Ono
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We report our Keck/MOSFIRE and Magellan/LDSS3 spectroscopy for an [OII] Blob, OIIB10, that is a high-$z$ galaxy with spatially extended [OII]$\lambda\lambda3726,3729$ emission over 30 kpc recently identified by a Subaru large-area narrowband survey. The systemic redshift of OIIB10 is $z=1.18$ securely determined with [OIII]$\lambda\lambda4959,5007$ and H$\beta$ emission lines. We identify FeII$\lambda$2587 and MgII$\lambda\lambda$2796,2804 absorption lines blueshifted from the systemic redshift...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1406.7052
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5.0
Jun 30, 2018
06/18
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Peter Kurczynski; Eric Gawiser; Marc Rafelski; Harry I. Teplitz; Viviana Acquaviva; Thomas M. Brown; Dan Coe; Duilia F. de Mello; Steven L. Finkelstein; Norman A. Grogin; Anton M. Koekemoer; Kyoung-soo Lee; Claudia Scarlata; Brian D. Siana
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We estimate the UV continuum slope, beta, for 923 galaxies in the range 1 < z < 8 in the Hubble Ultradeep Field (HUDF). These data include 460 galaxies at 1 < z < 2 down to an absolute magnitude M_{UV} = -14 (~0.006 L*_{z=1}; 0.02 L*_{z=0}), comparable to dwarf galaxies in the local universe. We combine deep HST/UVIS photometry in F225W, F275W, F336W wavebands (UVUDF) with recent data from HST/WFC3/IR (HUDF12). Galaxies in the range 1 < z < 2 are significantly bluer than local...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1407.3680
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4.0
Jun 30, 2018
06/18
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A. López; B. Tercero; Z. Kisiel; A. M. Daly; C. Bermúdez; H. Calcutt; N. Marcelino; S. Viti; B. J. Drouin; I. R. Medvedev; C. F. Neese; L. Pszczółkowski; J. L. Alonso; J. Cernicharo
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New laboratory data of CH$_2$CHCN (vinyl cyanide) in its ground and vibrationally excited states at the microwave to THz domain allow searching for these excited state transitions in the Orion-KL line survey. Frequency-modulated spectrometers combined into a single broadband 50-1900 GHz spectrum provided measurements of CH$_2$CHCN covering a spectral range of 18-1893 GHz, whose assignments was confirmed by Stark modulation spectra in the 18-40 GHz region and by ab-initio anharmonic force field...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1407.4363
