scholarly journals A remarkably flat relationship between the average star formation rate and AGN luminosity for distant X-ray AGN

2015 ◽  
Vol 453 (1) ◽  
pp. 591-604 ◽  
Author(s):  
F. Stanley ◽  
C. M. Harrison ◽  
D. M. Alexander ◽  
A. M. Swinbank ◽  
J. A. Aird ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
X Ray

scholarly journals Separating line emission from star formation, shocks, and AGN ionization in NGC 1068

2019 ◽  
Vol 487 (3) ◽  
pp. 4153-4168 ◽  
Author(s):  
Joshua J D’Agostino ◽  
Lisa J Kewley ◽  
Brent A Groves ◽  
Anne M Medling ◽  
Enrico Di Teodoro ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Three Dimensional ◽  
Line Emission ◽  
X Ray ◽  
Diagnostic Diagram ◽  
The Galaxy ◽  
Ngc 1068 ◽  
Many Sources

ABSTRACT In the optical spectra of galaxies, the separation of line emission from gas ionized by star formation and an active galactic nucleus (AGN), or by star formation and shocks, are very well-understood problems. However, separating line emission between AGN and shocks has proven difficult. With the aid of a new three-dimensional diagnostic diagram, we show the simultaneous separation of line emission from star formation, shocks, and AGN in NGC 1068, and quantify the ratio of star formation, shocks, and AGN in each spaxel. The AGN, shock, and star formation luminosity distributions across the galaxy accurately align with X-ray, radio, and CO(3–2) observations, respectively. Comparisons with previous separation methods show that the shocked emission heavily mixes with the AGN emission. We also show that if the H α flux is to be used as a star formation rate indicator, separating line emission from as many sources as possible should be attempted to ensure accurate results.

scholarly journals Sub-galactic scaling relations between X-ray luminosity, star formation rate, and stellar mass

2020 ◽  
Vol 494 (4) ◽  
pp. 5967-5984 ◽  
Author(s):  
K Kouroumpatzakis ◽  
A Zezas ◽  
P Sell ◽  
K Kovlakas ◽  
P Bonfini ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
High Mass ◽  
X Ray ◽  
Formation History ◽  
Low Mass ◽  
X Ray Binaries ◽  
Intrinsic Scatter

ABSTRACT X-ray luminosity (LX) originating from high-mass X-ray binaries (HMXBs) is tightly correlated with the host galaxy’s star formation rate (SFR). We explore this connection at sub-galactic scales spanning ∼7 dex in SFR and ∼8 dex in specific SFR (sSFR). There is good agreement with established relations down to SFR ≃ 10−3 M$_{\odot }\, \rm {yr^{-1}}$, below which an excess of X-ray luminosity emerges. This excess likely arises from low-mass X-ray binaries. The intrinsic scatter of the LX–SFR relation is constant, not correlated with SFR. Different star formation indicators scale with LX in different ways, and we attribute the differences to the effect of star formation history. The SFR derived from H α shows the tightest correlation with X-ray luminosity because H α emission probes stellar populations with ages similar to HMXB formation time-scales, but the H α-based SFR is reliable only for $\rm sSFR{\gt }10^{-12}$ M$_{\odot }\, \rm {yr^{-1}}$/M⊙.

scholarly journals The impact of quenching on galaxy profiles in the simba simulation

2020 ◽  
Vol 494 (4) ◽  
pp. 6053-6071 ◽  
Author(s):  
Sarah Appleby ◽  
Romeel Davé ◽  
Katarina Kraljic ◽  
Daniel Anglés-Alcázar ◽  
Desika Narayanan
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
High Redshift ◽  
Formation Rate ◽  
Gas Content ◽  
X Ray ◽  
Star Forming ◽  
Numerical Resolution ◽  
Radial Profiles ◽  
The Impact

ABSTRACT We study specific star formation rate (sSFR) and gas profiles of star-forming (SF) and green valley (GV) galaxies in the simba cosmological hydrodynamic simulation. SF galaxy half-light radii (Rhalf) at z = 0 and their evolution (∝(1 + z)−0.78) agree with observations. Passive galaxy Rhalf agree with observations at high redshift, but by z = 0 are too large, owing to numerical heating. We compare simbaz = 0 sSFR radial profiles for SF and GV galaxies to observations. simba shows strong central depressions in star formation rate (SFR), sSFR, and gas fraction in GV galaxies and massive SF systems, qualitatively as observed, owing to black hole X-ray feedback, which pushes central gas outwards. Turning off X-ray feedback leads to centrally peaked sSFR profiles as in other simulations. In conflict with observations, simba yields GV galaxies with strongly dropping sSFR profiles beyond ≳Rhalf, regardless of active galactic nucleus feedback. The central depression owes to lowering molecular gas content; the drop in the outskirts owes to reduced star formation efficiency. simba’s satellites have higher central sSFR and lower outskirts sSFR than centrals, in qualitative agreement with observations. At z = 2, simba does not show central depressions in massive SF galaxies, suggesting simba’s X-ray feedback should be more active at high-z. High-resolution tests indicate central sSFR suppression is not sensitive to numerical resolution. Reproducing the central sSFR depression in z = 0 GV galaxies represents a unique success of simba. The remaining discrepancies highlight the importance of SFR and gas profiles in constraining quenching mechanisms.

scholarly journals Deep ALMA photometry of distant X-ray AGN: improvements in star formation rate constraints, and AGN identification

2018 ◽  
Vol 478 (3) ◽  
pp. 3721-3739 ◽  
Author(s):  
F Stanley ◽  
C M Harrison ◽  
D M Alexander ◽  
J Simpson ◽  
K K Knudsen ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
X Ray ◽  
Rate Constraints

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 ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Compact Objects ◽  
Host Galaxies ◽  
X Ray ◽  
Multi Wavelength ◽  
Accretion Physics ◽  
Stellar Properties

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.

scholarly journals The mean star formation rate of X-ray selected active galaxies and its evolution fromz ~ 2.5: results from PEP-Herschel

2012 ◽  
Vol 545 ◽  
pp. A45 ◽  
Author(s):  
D.J. Rosario ◽  
P. Santini ◽  
D. Lutz ◽  
L. Shao ◽  
R. Maiolino ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Active Galaxies ◽  
X Ray ◽  
The Mean

scholarly journals X-ray Luminosity Functions and Star Formation Rate

2005 ◽  
Vol 1 (S230) ◽  
pp. 353-358 ◽  
Author(s):  
H.-J. Grimm ◽  
M. Gilfanov ◽  
R. Sunyaev
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
X Ray ◽  
Luminosity Functions

scholarly journals X-ray binaries as the origin of nebular He II emission in low-metallicity star-forming galaxies

2019 ◽  
Vol 622 ◽  
pp. L10 ◽  
Author(s):  
D. Schaerer ◽  
T. Fragos ◽  
Y. I. Izotov
Keyword(s):  
Star Formation ◽  
Empirical Data ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Theoretical Models ◽  
High Mass ◽  
X Ray ◽  
Star Forming ◽  
Low Metallicity ◽  
X Ray Binaries

The origin of nebular He II emission, which is frequently observed in low-metallicity (O/H) star-forming galaxies, remains largely an unsolved question. Using the observed anticorrelation of the integrated X-ray luminosity per unit of star formation rate (LX/SFR) of an X-ray binary population with metallicity and other empirical data from the well-studied galaxy I Zw 18, we show that the observed He II λ4686 intensity and its trend with metallicity is naturally reproduced if the bulk of He+ ionizing photons are emitted by the X-ray sources. We also show that a combination of X-ray binary population models with normal single and/or binary stellar models reproduces the observed I(4686)/I(Hβ) intensities and its dependency on metallicity and age. We conclude that both empirical data and theoretical models suggest that high-mass X-ray binaries are the main source of nebular He II emission in low-metallicity star-forming galaxies.

scholarly journals A hint on the metal-free star formation rate density from 21-cm-EDGES data

2020 ◽  
Vol 496 (2) ◽  
pp. 1445-1452 ◽  
Author(s):  
Atrideb Chatterjee ◽  
Pratika Dayal ◽  
Tirthankar Roy Choudhury ◽  
Raffaella Schneider
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Monte Carlo Analysis ◽  
Host Galaxies ◽  
X Ray ◽  
Metal Free ◽  
Global Signal ◽  
Radio Background ◽  
X Ray Background

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.

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