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Related papers: Variable AGN in the GALEX Time Domain Survey

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This paper presents a survey of X-ray selected active galactic nuclei (AGN) with optical spectroscopic follow-up in a $\sim 18\, \rm{deg^2}$ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by…

We assemble a sample of 733 dwarf galaxies ($M_{\ast} \le 10^{9.5} \text{M}_\odot$) with signatures of active galactic nuclei (AGN) and explore the intersection between different AGN selection techniques. Objects in our database are…

Astrophysics of Galaxies · Physics 2024-05-31 Erik J. Wasleske , Vivienne F. Baldassare

We study a sample of 23 narrow-emission line galaxies (NELGs) which were selected by their strong variability as QSO candidates in the framework of a variability-and-proper motion QSO survey on digitised Schmidt plates. In previous work, we…

Astrophysics · Physics 2009-11-07 H. Meusinger , J. Brunzendorf

Compared with numerous X-ray dominant active galactic nuclei (AGNs) without emission-line signatures in their optical spectra, the X-ray selected AGNs with optical emission lines are probably still in the high-accretion phase of black hole…

Astrophysics of Galaxies · Physics 2017-05-17 Feng Li , Qirong Yuan , Weihao Bian , Xi Chen , Pengfei Yan

We use observations from the 9 square degree multiwavelength survey in Bootes to identify hundreds of obscured active galactic nuclei (AGN) with high redshifts (z > 0.7), luminosities (L_bol > 10^45 ergs/s), and moderate obscuring columns…

We have compiled a large sample of low-redshift active galactic nuclei (AGN) identified via their emission line characteristics from the spectroscopic data of the Sloan Digital Sky Survey. Since emission lines are often contaminated by…

We use stellar population synthesis modeling to analyze the host galaxy properties of a sample of 33 UV-selected, narrow-lined active galactic nuclei (AGNs) at z ~ 2 - 3. In order to quantify the contribution of AGN emission to host galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Kevin N. Hainline , Alice E. Shapley , Jenny E. Greene , Charles C. Steidel , Naveen A. Reddy , Dawn K. Erb

We present the second Galaxy Evolution Explorer (GALEX) Ultraviolet Variability (GUVV-2) Catalog that contains information on 410 newly discovered time-variable sources gained through simultaneous near (NUV 1750-2750A) and far (FUV…

Astrophysics · Physics 2009-11-13 Jonathan M. Wheatley , Barry Y. Welsh , Stanley E. Browne

We present the observed fraction of galaxies with an Active Galactic Nucleus (AGN) as a function of environment in the Early Data Release of the Sloan Digital Sky Survey (SDSS). Using 4921 galaxies between 0.05 <= z <= 0.095, and brighter…

We present an analysis of the long-term optical variability for $\sim50,000$ nearby (z<0.055) galaxies from the NASA-Sloan Atlas, $35,000$ of which are low-mass ($M_{\ast}<10^{10}~M_{\odot}$). We use difference imaging of Palomar Transient…

High Energy Astrophysical Phenomena · Physics 2020-06-17 Vivienne F. Baldassare , Marla Geha , Jenny Greene

This is the first paper in a dedicated series to study the properties of the optically selected BLR-less AGNs (Active Galactic Nuclei with no-hidden central broad emission line regions). We carried out a systematic search for the BLR-less…

Astrophysics of Galaxies · Physics 2015-06-17 Xue Guang Zhang

While it is difficult to observe the first black hole seeds in the early Universe, we can study intermediate mass black holes (IMBHs) in local dwarf galaxies for clues about their origins. In this paper we present a sample of…

The detection of X-ray emission constitutes a reliable and efficient tool for the selection of Active Galactic Nuclei (AGNs), although it may be biased against the most heavily absorbed AGNs. Simple mid-IR broad-band selection criteria…

Astrophysics of Galaxies · Physics 2020-05-06 E. Pouliasis , G. Mountrichas , I. Georgantopoulos , A. Ruiz , M. Yang , A. Z. Bonanos

We develop a simple method to search for changing-look (CL) active galactic nucleus (AGN) candidates, and conduct a test run. In this method, optical variations of AGNs are monitored and CL-AGNs may appear to have a pattern of being bluer…

Astrophysics of Galaxies · Physics 2024-12-18 Li-tao Zhu , Zhongxiang Wang , P. U. Devanand , Alok C. Gupta , Karan Dogra , Jie Li , Ju-Jia Zhang , Shun-hao Ji , Si-si Sun

We report on candidate active galactic nuclei (AGN) discovered during the monitoring of $\sim$500 bright (r < 18 mag) galaxies over several years with the Kepler Mission. Most of the targets were sampled every 30 minutes nearly continuously…

High Energy Astrophysical Phenomena · Physics 2015-12-09 Edward J. Shaya , Robert Olling , Richard Mushotzky

Luminous AGNs are usually selected by their non-stellar colours or their X-ray emission. Colour selection cannot be used to select low-luminosity AGNs, since their emission is dominated by the host galaxy. Objects with low X-ray to optical…

Astrophysics of Galaxies · Physics 2009-11-13 K. Boutsia , B. Leibundgut , D. Trevese , F. Vagnetti

We present a catalog of physical properties for galaxies hosting active galactic nuclei (AGN) detected by the Wide-field Infrared Survey Explorer (WISE). By fitting broadband spectral energy distributions of sources in the WISE AGN Catalog…

Astrophysics of Galaxies · Physics 2021-12-08 R. Scott Barrows , Julia M. Comerford , Daniel Stern , Roberto J. Assef

We have constructed a catalog of active galactic nuclei (AGNs) with $z < 0.13$, based on optical spectroscopy, from the parent sample of galaxies in the 6dF galaxy survey (Final Release of 6dFGS), a census of the Southern hemisphere. This…

Astrophysics of Galaxies · Physics 2022-02-02 Yan-Ping Chen , Ingyin Zaw , Glennys R Farrar , Sana Elgamal

We report the results of a Sloan Digital Sky Survey-IV eBOSS program to target X-ray sources and mid-infrared-selected WISE AGN candidates in a 36.8 deg$^2$ region of Stripe 82. About half this survey (15.6 deg$^2$) covers the largest…

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