scholarly journals A 12μm Flux Limited Sample of Galaxies: Preliminary Results on the IR Luminosity Function

1989 ◽  
Vol 134 ◽  
pp. 55-56
Author(s):  
L. Spinoglio ◽  
M. A. Malkan
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Complete Sample ◽  
Limited Sample ◽  
Near Ir ◽  
Luminosity Functions ◽  
Definition Of ◽  
Optical Spectrophotometry ◽  
Ir Photometry

An all-sky 12μm flux-limited sample of 392 galaxies has been selected from the IRAS Point Source Catalog. More than 20% of the sample harbor active nuclei (with Seyfert 1 or 2 or LINER emission-line spectra). Thus one byproduct of this work is the definition of a large complete sample of bright active galaxies, with roughly equal percentages of Sy 1's, Sy 2's and LINERs. Since we now have virtually all (93%) the redshifts for the sample galaxies, the far-infrared luminosity functions of all classes of galaxies have been derived using IRAS coadded data. Since our luminosity functions for Sy 1 and Sy 2 are indistinguishable from those of the optically selected CfA sample, the 12μm selection appears to be an efficient and complete technique for finding active galactic nuclei. Optical spectrophotometry and near-IR photometry of the sample is being obtained to compute accurate bolometric luminosities.

scholarly journals The Southern 2MASS Active Galactic Nuclei Survey: Spectroscopic Follow-up with Six Degree Field

2010 ◽  
Vol 27 (3) ◽  
pp. 302-320 ◽  
Author(s):  
Frank J. Masci ◽  
Roc M. Cutri ◽  
Paul J. Francis ◽  
Brant O. Nelson ◽  
John P. Huchra ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Type I ◽  
Galactic Latitude ◽  
Stellar Objects ◽  
Identification Rate ◽  
Near Ir ◽  
The Uk ◽  
Probable Type

AbstractThe Two Micron All-Sky Survey (2MASS) has provided a uniform photometric catalog to search for previously unknown red active galactic nuclei (AGN) and Quasi-Stellar Objects (QSOs).We have extended the search to the southern equatorial sky by obtaining spectra for 1182 AGN candidates using the six degree field (6dF) multifibre spectrograph on the UK Schmidt Telescope. These were scheduled as auxiliary targets for the 6dF Galaxy Redshift Survey. The candidates were selected using a single color cut of J – Ks > 2 to Ks ≲ 15.5 and a galactic latitude of lbl > 30°. 432 spectra were of sufficient quality to enable a reliable classification. 116 sources (∼27%) were securely classified as type I AGN, 20 as probable type I AGN, and 57 as probable type II AGN. Most of them span the redshift range 0.05 < z < 0.5 and only 8 (∼6%) were previously identified as AGN or QSOs. Our selection leads to a significantly higher AGN identification rate amongst local galaxies (>20%) than in any previous (mostly blue-selected) galaxy survey. A small fraction of the type I AGN could have their optical colors reddened by optically thin dust with AV < 2 mag relative to optically selected QSOs. A handful show evidence of excess far-infrared (IR) emission. The equivalent width (EW) and color distributions of the type I and II AGN are consistent with AGN unified models. In particular, the EW of the [Oiii] emission line weakly correlates with optical–near-IR color in each class of AGN, suggesting anisotropic obscuration of the AGN continuum. Overall, the optical properties of the 2MASS red AGN are not dramatically different from those of optically-selected QSOs. Our near-IR selection appears to detect the most near-IR luminous QSOs in the local universe to z≃0.6 and provides incentive to extend the search to deeper near-IR surveys.

scholarly journals MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

2012 ◽  
Vol 754 (1) ◽  
pp. 45 ◽  
Author(s):  
Kohei Ichikawa ◽  
Yoshihiro Ueda ◽  
Yuichi Terashima ◽  
Shinki Oyabu ◽  
Poshak Gandhi ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Complete Sample

scholarly journals Evolution of the AGN UV luminosity function from redshift 7.5

2019 ◽  
Vol 488 (1) ◽  
pp. 1035-1065 ◽  
Author(s):  
Girish Kulkarni ◽  
Gábor Worseck ◽  
Joseph F Hennawi
Keyword(s):  
Active Galactic Nuclei ◽  
Luminosity Function ◽  
Galactic Nuclei ◽  
Systematic Errors ◽  
Selection Function ◽  
Data Sets ◽  
Multiple Data ◽  
Luminosity Functions ◽  
Multiple Data Sets ◽  
Photoionization Rate

ABSTRACTDeterminations of the ultraviolet (UV) luminosity function of active galactic nuclei (AGN) at high redshifts are important for constraining the AGN contribution to reionization and understanding the growth of supermassive black holes. Recent inferences of the luminosity function suffer from inconsistencies arising from inhomogeneous selection and analysis of data. We address this problem by constructing a sample of more than 80 000 colour-selected AGN from redshift $z$ = 0 to 7.5 using multiple data sets homogenized to identical cosmologies, intrinsic AGN spectra, and magnitude systems. Using this sample, we derive the AGN UV luminosity function from redshift $z$ = 0 to 7.5. The luminosity function has a double power-law form at all redshifts. The break magnitude M* shows a steep brightening from M* ∼ −24 at $z$ = 0.7 to M* ∼ −29 at $z$ = 6. The faint-end slope β significantly steepens from −1.9 at $z$ < 2.2 to −2.4 at $z$ ≃ 6. In spite of this steepening, the contribution of AGN to the hydrogen photoionization rate at $z$ ∼ 6 is subdominant (<3 per cent), although it can be non-negligible (∼10 per cent) if these luminosity functions hold down to M1450 = −18. Under reasonable assumptions, AGN can reionize He ii by redshift $z$ = 2.9. At low redshifts ($z$ < 0.5), AGN can produce about half of the hydrogen photoionization rate inferred from the statistics of H i absorption lines in the intergalactic medium. Our analysis also reveals important systematic errors in the data, which need to be addressed and incorporated in the AGN selection function in future in order to improve our results. We make various fitting functions, codes, and data publicly available.

scholarly journals Multifrequency Variability of AGN's: Continuum Variations from the Near IR to the X-rays

1994 ◽  
Vol 159 ◽  
pp. 131-143
Author(s):  
J. Clavel
Keyword(s):  
Active Galactic Nuclei ◽  
Temporal Evolution ◽  
Line Emission ◽  
Galactic Nuclei ◽  
The Other ◽  
X Rays ◽  
Optical Telescope ◽  
Emission Process ◽  
Near Ir ◽  
The Continuum

Because they emit copiously over more than 10 decades in frequency, Active Galactic Nuclei (AGN) cannot be understood without the help of multiwavelength observations. On the other hand, variability monitoring has also proven to be invaluable in understanding the continuum and line emission process as well as the geometry of the innermost regions in these objects. Indeed, at the heart of AGN's lies an object which is so compact that the only way to probe its structure is the study of the temporal evolution of its spectrum. The equivalent resolution which can be achieved in this way is of the order of 10 microarcsecs, far beyond the capability of any UV or optical telescope.

scholarly journals AKARI Infrared Views of AGNs

2009 ◽  
Vol 5 (S267) ◽  
pp. 129-129
Author(s):  
Shinki Oyabu
Keyword(s):  
Infrared Spectroscopy ◽  
Active Galactic Nuclei ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Sky Survey

AbstractThe Japanese infrared satellite AKARI has unique capabilities for near-infrared spectroscopy and an all-sky survey in the mid- and far-infrared. We present the recent results on active galactic nuclei that use the unique capabilities of AKARI.

scholarly journals THE OPTX PROJECT. II. HARD X-RAY LUMINOSITY FUNCTIONS OF ACTIVE GALACTIC NUCLEI FORz≲ 5

2009 ◽  
Vol 698 (1) ◽  
pp. 380-396 ◽  
Author(s):  
B. Yencho ◽  
A. J. Barger ◽  
L. Trouille ◽  
L. M. Winter
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
Luminosity Functions
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