Tracing the Mass‐Dependent Star Formation History of Late‐Type Galaxies Using X‐Ray Emission: Results from the Chandra Deep Fields

Lehmer, Bret; Brandt, W. N.; Alexander, D. M.; Bell, Eric F.; Hornschemeier, A. E.; McIntosh, Daniel H.; Bauer, F. E.; Gilli, R.; Mainieri, V.; Schneider, Donald P.; Silverman, John D.; Steffen, A. T.; Tozzi, P.; Wolf, Christian

doi:10.1086/588459

Cited by 84 publications

(125 citation statements)

References 167 publications

(247 reference statements)

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“…Similar behavior is also noted in an earlier analysis of the stacked X-ray properties of early-type galaxies in a 1.4 deg 2 field in the NOAO Deep Wide-Field Survey (Brand et al 2005). (Note, however, in a study of late-type galaxies, Lehmer et al (2008) find no evidence for evolution of the AGN fraction over the redshift range 0.1 < z < 0.8.) In the left panel of Figure 13, we show curves for PLE (∝ (1 + z) 3 ; gray dotted line) and for LDDE, another popular model for the evolution of the AGN XLF (∝ (1 + z) 4 ; gray dashed line).…”

Section: Comparison To Previous Field Fractionssupporting

confidence: 83%

THE FIELD X-RAY AGN FRACTION TOz= 0.7 FROM THECHANDRAMULTIWAVELENGTH PROJECT AND THE SLOAN DIGITAL SKY SURVEY

Haggard

Green

Anderson

et al. 2010

ApJ

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We employ the Chandra Multiwavelength Project (ChaMP) and the Sloan Digital Sky Survey (SDSS) to study the fraction of X-ray-active galaxies in the field to z = 0.7. We utilize spectroscopic redshifts from SDSS and ChaMP, as well as photometric redshifts from several SDSS catalogs, to compile a Parent sample of more than 100,000 SDSS galaxies and nearly 1600 Chandra X-ray detections. Detailed ChaMP volume completeness maps allow us to investigate the local fraction of active galactic nuclei (AGNs), defined as those objects having broadband X-ray luminosities L X (0.5-8 keV) 10 42 erg s −1 , as a function of absolute optical magnitude, X-ray luminosity, redshift, mass, and host color/morphological type. In five independent samples complete in redshift and i-band absolute magnitude, we determine the field AGN fraction to be between 0.16% ± 0.06% (for z 0.125 and −18 > M i > −20) and 3.80% ± 0.92% (for z 0.7 and M i < −23). We find excellent agreement between our ChaMP/SDSS field AGN fraction and the Chandra cluster AGN fraction, for samples restricted to similar redshift and absolute magnitude ranges: 1.19% ± 0.11% of ChaMP/SDSS field galaxies with 0.05 < z < 0.31 and absolute R-band magnitude more luminous than M R < −20 are AGNs. Our results are also broadly consistent with measures of the field AGN fraction in narrow, deep fields, though differences in the optical selection criteria, redshift coverage, and possible cosmic variance between fields introduce larger uncertainties in these comparisons.

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Section: Comparison To Previous Field Fractionssupporting

confidence: 83%

THE FIELD X-RAY AGN FRACTION TOz= 0.7 FROM THECHANDRAMULTIWAVELENGTH PROJECT AND THE SLOAN DIGITAL SKY SURVEY

Haggard

Green

Anderson

et al. 2010

ApJ

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“…Webb et al (2009) showed that all of the 8 μm detected LABs have rest-frame near-IR colors consistent with an AGN or ULIRG spectral energy distributions (SED). To examine the possibility that LAB 1, LAB 5, and LAB 16 host heavily obscured AGN (or low-luminosity AGN below the detection limit) we stack the X-ray map at these three positions using the technique outlined in Lehmer et al (2008). We find a marginally significant (93.6% confidence) excess of 6.6 counts compared to 3.5 expected from the background.…”

Section: Searching For X-ray Undetected Agn In Labsmentioning

confidence: 92%

THECHANDRADEEP PROTOCLUSTER SURVEY: Lyα BLOBS ARE POWERED BY HEATING, NOT COOLING

Geach

Alexander

Lehmer

et al. 2009

ApJ

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We present the results of a 400 ks Chandra survey of 29 extended Lyα emitting nebulae (Lyα Blobs, LABs) in the z = 3.09 protocluster in the SS A22 field. We detect luminous X-ray counterparts in five LABs, implying a large fraction of active galactic nuclei (AGN) in LABs, f AGN = 17 +12 −7 % down to L 2-32 keV ∼ 10 44 erg s −1 . All of the AGN appear to be heavily obscured, with spectral indices implying obscuring column densities of N H > 10 23 cm −2 . The AGN fraction should be considered a lower limit, since several more LABs not detected with Chandra show AGN signatures in their mid-infrared (mid-IR) emission. We show that the UV luminosities of the AGN are easily capable of powering the extended Lyα emission via photoionization alone. When combined with the UV flux from a starburst component, and energy deposited by mechanical feedback, we demonstrate that "heating" by a central source, rather than gravitational cooling is the most likely power source of LABs. We argue that all LABs could be powered in this manner, but that the luminous host galaxies are often just below the sensitivity limits of current instrumentation, or are heavily obscured. No individual LABs show evidence for extended X-ray emission, and a stack equivalent to a 9 Ms exposure of an average LAB also yields no statistical detection of a diffuse X-ray component. The resulting diffuse X-ray/Lyα luminosity limit implies there is no hot (T 10 7 K) gas component in these halos, and also rules out inverse Compton scattering of cosmic microwave background photons, or local far-IR photons, as a viable power source for LABs.

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“…A detailed description of the expected spectra of the different components may be found in Persic & Rephaeli (2002). The relative importance of the spectral components may vary; however, in most cases the average flux ratio between the 0.5-2.0 keV and the 2.0-10 keV bands is the same that would be obtained if the spectrum was a power-law spectrum with spectral index Γ = 2.1 and negligible absorption (RCS03; Lehmer et al 2008). This does not imply the lack of X-ray absorption of X-rays in SF galaxies: M 82 and NGC 3256 are notable examples (RCS03; Ranalli et al 2008).…”

Section: X-ray Characterization Of the Selected Sourcesmentioning

confidence: 99%

X-ray properties of radio-selected star forming galaxies in theChandra-COSMOS survey

Ranalli

Comastri

Zamorani

et al. 2012

A&A

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X-ray surveys contain sizable numbers of star forming galaxies, beyond the AGN which usually make the majority of detections. Many methods to separate the two populations are used in the literature, based on X-ray and multiwavelength properties. We aim at a detailed test of the classification schemes and to study the X-ray properties of the resulting samples. We build on a sample of galaxies selected at 1.4 GHz in the VLA-COSMOS survey, classified by Smolčić et al. (2008, ApJS, 177, 14) according to their optical colours and observed with Chandra. A similarly selected control sample of AGN is also used for comparison. We review some X-ray based classification criteria and check how they affect the sample composition. The efficiency of the classification scheme devised by Smolčić et al. is such that ∼30% of composite/misclassified objects are expected because of the higher X-ray brightness of AGN with respect to galaxies. The latter fraction is actually 50% in the X-ray detected sources, while it is expected to be much lower among X-ray undetected sources. Indeed, the analysis of the stacked spectrum of undetected sources shows, consistently, strongly different properties between the AGN and galaxy samples. X-ray based selection criteria are then used to refine both samples. The radio/X-ray luminosity correlation for star forming galaxies is found to hold with the same X-ray/radio ratio valid for nearby galaxies. Some evolution of the ratio may be possible for sources at high redshift or high luminosity, tough it is likely explained by a bias arising from the radio selection. Finally, we discuss the X-ray number counts of star forming galaxies from the VLA-and C-COSMOS surveys according to different selection criteria, and compare them to the similar determination from the Chandra deep fields. The classification scheme proposed here may find application in future works and surveys.

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Tracing the Mass‐Dependent Star Formation History of Late‐Type Galaxies Using X‐Ray Emission: Results from the Chandra Deep Fields

Cited by 84 publications

References 167 publications

THE FIELD X-RAY AGN FRACTION TOz= 0.7 FROM THECHANDRAMULTIWAVELENGTH PROJECT AND THE SLOAN DIGITAL SKY SURVEY

THE FIELD X-RAY AGN FRACTION TOz= 0.7 FROM THECHANDRAMULTIWAVELENGTH PROJECT AND THE SLOAN DIGITAL SKY SURVEY

THECHANDRADEEP PROTOCLUSTER SURVEY: Lyα BLOBS ARE POWERED BY HEATING, NOT COOLING

X-ray properties of radio-selected star forming galaxies in theChandra-COSMOS survey

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