Ultraluminous X-ray source populations in the Chandra Source Catalog 2.0

2018 ◽  
Vol 14 (S346) ◽  
pp. 247-251
Author(s):  
Konstantinos Kovlakas ◽  
Andreas Zezas ◽  
Jeff J. Andrews ◽  
Antara Basu-Zych ◽  
Tassos Fragos ◽  
...  

Abstract. The nature and evolution of ultraluminous X-ray sources (ULXs) is an open problem in astrophysics. They challenge our current understanding of stellar compact objects and accretion physics. The recent discovery of pulsar ULXs further demonstrates the importance of this intriguing and rare class of objects.In order to overcome the difficulties of directly studying the optical associations of ULXs, we generally resort in statistical studies of the stellar properties of their host galaxies. We present the largest such study based on the combination of Chandra archival data with the most complete galaxy catalog of the Local Universe. Incorporating robust distances and stellar population parameters based on associated multi-wavelength information, and we explore the association of ULXs with galaxies in the (star formation rate, stellar mass, metallicity) space.We confirm the known correlation with morphology, star formation rate and stellar mass, while we find an excess of ULXs in dwarf galaxies, indicating dependence on age and metallicity.

2019 ◽  
Vol 15 (S356) ◽  
pp. 295-298
Author(s):  
Betelehem Bilata-Woldeyes ◽  
Mirjana Pović ◽  
Zeleke Beyoro-Amado ◽  
Tilahun Getachew-Woreta ◽  
Shimeles Terefe

AbstractStudying the morphology of a large sample of active galaxies at different wavelengths and comparing it with active galactic nuclei (AGN) properties, such as black hole mass (MBH) and Eddington ratio (λEdd), can help us in understanding better the connection between AGN and their host galaxies and the role of nuclear activity in galaxy formation and evolution. By using the BAT-SWIFT hard X-ray public data and by extracting those parameters measured for AGN and by using other public catalogues for parameters such as stellar mass (M*), star formation rate (SFR), bolometric luminosity (Lbol), etc., we studied the multiwavelength morphological properties of host galaxies of ultra-hard X-ray detected AGN and their correlation with other AGN properties. We found that ultra hard X-ray detected AGN can be hosted by all morphological types, but in larger fractions (42%) they seem to be hosted by spirals in optical, to be quiet in radio, and to have compact morphologies in X-rays. When comparing morphologies with other galaxy properties, we found that ultra hard X-ray detected AGN follow previously obtained relations. On the SFR vs. stellar mass diagram, we found that although the majority of sources are located below the main sequence (MS) of star formation (SF), still non-negligible number of sources, with diverse morphologies, is located on and/or above the MS, suggesting that AGN feedback might have more complex influence on the SF in galaxies than simply quenching it, as it was suggested in some of previous studies.


2021 ◽  
Vol 57 (1) ◽  
pp. 157-166
Author(s):  
Xin-Fa Deng ◽  
Xiao-Qing Wen

Using the apparent-magnitude limited active galactic nucleus (AGN) host galaxy sample of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12), we investigate the environmental dependence of age, stellar mass, the star formation rate (SFR) and stellar velocity dispersion of AGN host galaxies. We divide the whole apparent-magnitude limited AGN sample into many subsamples with a redshift binning size of Δz = 0.01, and analyse the environmental dependence of these galaxy properties of subsamples in each redshift bin. It turns out that these parameters of AGN host galaxies seemingly only have a weak environmental dependence.


2015 ◽  
Vol 11 (S319) ◽  
pp. 45-48
Author(s):  
Daniel Schaerer ◽  
Stephane de Barros ◽  
Frederic Boone

AbstractWe stress the importance of consistent SED analysis for distant star-forming galaxies (SFGs). We then summarise recent results from such an analysis concerning their basic physical properties, such as the determination of star formation rate (SFR), stellar mass, specific star SFR, UV attenuation, and how this affects our knowledge of star formation properties at high-z.


2019 ◽  
Vol 626 ◽  
pp. A61 ◽  
Author(s):  
L. Morselli ◽  
P. Popesso ◽  
A. Cibinel ◽  
P. A. Oesch ◽  
M. Montes ◽  
...  

High-resolution multi-wavelength photometry is crucial to explore the spatial distribution of star formation in galaxies and understand how these evolve. To this aim, in this paper we exploit the deep, multi-wavelength Hubble Space Telescope (HST) data available in the central parts of the Great Observatories Origins Deep Survey (GOODS) fields and study the distribution of star formation activity and mass in galaxies located at different positions with respect to the main sequence (MS) of star-forming galaxies. Our sample consists of galaxies with stellar mass ≥109.5 M⊙ in the redshift range 0.2 ≤ z ≤ 1.2. Exploiting 10-band photometry from the UV to the near-infrared at HST resolution, we derived spatially resolved maps of galaxy properties, such as stellar mass and star formation rate and specific star formation rate, with a resolution of ∼0.16 arcsec. We find that the star formation activity is centrally enhanced in galaxies above the MS and centrally suppressed below the MS, with quiescent galaxies (1 dex below the MS) characterised by the highest suppression. The specific star formation rate in the outer region does not show systematic trends of enhancement or suppression above or below the MS. The distribution of mass in MS galaxies indicates that bulges grow when galaxies are still on the MS relation. Galaxies below the MS are more bulge-dominated with respect to MS counterparts at fixed stellar mass, while galaxies in the upper envelope are more extended and have Sérsic indices that are always smaller than or comparable to their MS counterparts. The suppression of star formation activity in the central region of galaxies below the MS hints at inside-out quenching, as star formation is still ongoing in the outer regions.


2013 ◽  
Vol 9 (S296) ◽  
pp. 222-225
Author(s):  
I. Leonidaki ◽  
P. Boumis ◽  
A. Zezas

AbstractWe present the largest sample of multi-wavelength Supernova Remnants (SNRs) in six nearby galaxies, based on Chandra archival data and deep optical narrow-band Hα and [Sii] images as well as spectroscopic observations. We have identified 37 X-ray selected thermal SNRs, 30 of which are new identifications and ~ 400 optical SNRs, for 67 of which we spectroscopically verified their shock-excited nature. We discuss the properties of the X-ray/optically detected SNRs in different types of galaxies and hence different environments, in order to address their dependence on their Interstellar Medium (ISM). We also discuss the SNR populations in the context of the star formation rate of their host galaxies. We cross-correlate parameters of the optically detected SNRs with parameters of coincident X-ray emitting SNRs in order to understand their evolution and investigate possible selection effects.


2019 ◽  
Vol 491 (3) ◽  
pp. 3419-3434 ◽  
Author(s):  
M Celeste Artale ◽  
Michela Mapelli ◽  
Yann Bouffanais ◽  
Nicola Giacobbo ◽  
Mario Pasquato ◽  
...  

ABSTRACT We investigate the properties of the host galaxies of compact binary mergers across cosmic time, by means of population-synthesis simulations combined with galaxy catalogues from the eagle suite. We analyse the merger rate per galaxy of binary neutron stars (BNSs), black hole–neutron star binaries (BHNSs), and binary black holes (BBHs) from redshift zero up to six. The binary merger rate per galaxy strongly correlates with the stellar mass of the host galaxy at any redshift considered here. This correlation is significantly steeper for BNSs than for both BHNSs and BBHs. Moreover, we find that the merger rate per galaxy depends also on host galaxy’s star formation rate (SFR) and metallicity. We derive a robust fitting formula that relates the merger rate per galaxy with galaxy’s SFR, stellar mass, and metallicity at different redshifts. The typical masses of the host galaxies increase significantly as redshift decreases, as a consequence of the interplay between delay time distribution of compact binaries and cosmic assembly of galaxies. Finally, we study the evolution of the merger rate density with redshift. At low redshift (z ≤ 0.1) early-type galaxies give a larger contribution to the merger rate density than late-type galaxies. This trend reverts at z ≥ 1.


2020 ◽  
Vol 496 (2) ◽  
pp. 1445-1452 ◽  
Author(s):  
Atrideb Chatterjee ◽  
Pratika Dayal ◽  
Tirthankar Roy Choudhury ◽  
Raffaella Schneider

ABSTRACT We aim to provide here the first data-constrained estimate of the metal-free (Population III; Pop III) star formation rate density $\dot{\rho }_{*}^{III}$ required at high redshifts ($z \lower.5ex\hbox{$\,\, \buildrel\gt \over \sim \,\,$}16$) in order to reproduce both the amplitude and the redshift of the EDGES 21-cm global signal. Our model accounts for the Ly α, radio, and X-ray backgrounds from both Pop III and metal-enriched Population II (Pop II) stars. For the latter, we use the star formation rate density estimates (and the Ly α background) from the Delphi semi-analytic model that has been shown to reproduce all key observables for galaxies at $z \lower.5ex\hbox{$\,\, \buildrel\gt \over \sim \,\,$}5$; the radio and X-ray backgrounds are fixed using low-z values. The constraints on the free parameters characterizing the properties of the Pop III stars are obtained using a Markov Chain Monte Carlo analysis. Our results yield a $\dot{\rho }_{*}^{III}$ that while increasing from z ∼ 21 to 16 thereafter shows a sharp decline which is in excellent agreement with the results found by Valiante et al. to simulate the growth of z ∼ 6–7 quasars and their host galaxies, suggesting that the bulk of Pop III star formation occurs in the rarest and most massive metal-poor haloes at z ≲ 20. This allows Pop III stars to produce a rapidly growing Ly α background between z ∼ 21 and 15. Further, Pop III stars are required to provide a radio background that is about 3–4 orders of magnitude higher than that provided by Pop II stars although Pop II stars dominate the X-ray background.


2019 ◽  
Vol 15 (S356) ◽  
pp. 173-173
Author(s):  
Hassen Yesuf

AbstractWe analyze the molecular and atomic gas data from the GALEX Arecibo SDSS Survey (xGASS) and the extended CO Legacy Database (xCOLD GASS) IRAM survey using novel survival analysis techniques to identify a small number of stellar properties that best correlate with the gas mass. We find that the dust absorption, AV, and the stellar half-light radius, R50, are likely the two best secondary parameters than improve the Kennicutt - Schmidt type relation between the gas mass and the star formation rate, SFR. We fit multiple regression, taking into account gas mass upper limits, to summarize the median, mean, and the 0.15/0.85 quantile multivariate relationships between the gas mass (atomic or molecular hydrogen), SFR, AV and/or R50. In particular, we find that the AV of both the stellar continuum and nebular gas emission shows a significant partial correlation with the molecular hydrogen after controlling for the effect of SFR. The partial correlation between the AV and the atomic gas, however, is weak and their zero-order correlation may be explained by SFR. This is expected since in poorly dust-shielded regions molecular hydrogen is dissociated by the far ultraviolet photons and HI is the dominant phase. Similarly, R50 shows significant partial correlations with both atomic and molecular gas masses. This hints at the importance of environment (e.g., galacto-centric distance) on the gas contents galaxies and on the interplay between gas and star formation rate. We apply the gas scaling relations we found to a large sample of type 2 and type 1 AGNs and infer that the gas mass correlates with AGN luminosity. This correlation is inconsistent with the prediction of AGN feedback models that strong AGNs remove or heat cold gas in their host galaxies.


2009 ◽  
Vol 5 (S267) ◽  
pp. 80-84
Author(s):  
Vincenzo Mainieri ◽  

AbstractWe present a large sample of X-ray selected type 2 QSOs from the XMM–COSMOS survey. Type 2 QSOs are luminous AGN whose central engines are obscured by large amounts of gas and dust. The selection criteria we have used are based on high X-ray luminosity (LX > 1044 erg s−1) and heavy obscuration (NH > 1022 cm−2). We derived stellar masses and star-formation rate estimates for the host galaxies from the best fit of the observed photometry. Type 2 QSOs are generally hosted in massive galaxies with on-going star formation.


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