Clues to Active Galactic Nucleus Growth from Optically Variable Objects in the Hubble Ultra Deep Field

Cohen, Seth H.; Ryan, Russell E.; Straughn, Amber N.; Hathi, N. P.; Windhorst, Rogier A.; Koekemoer, Anton M.; Pirzkal, Norbert; Xu, Chun; Mobasher, Bahram; Malhotra, Sangeeta; Strolger, Louis-Gregory; Rhoads, James E.

doi:10.1086/499577

Cited by 23 publications

(32 citation statements)

References 24 publications

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“…Variability is indeed a defining property of AGNs that is often used for their discovery. For instance, Cohen et al (2006) search for variable galaxies in the Hubble Ultra Deep Field to investigate the presence of AGN and find 45 solid candidates. Those AGN candidates show characteristic variability of Δmag∼0.01-0.8 mag.…”

Section: Nuclear Emission and Nuclear Variabilitymentioning

confidence: 99%

The Abell 85 Bcg: A Nucleated, Coreless Galaxy

Madrid

Donzelli

2016

ApJ

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New high-resolution r-band imaging of the brightest cluster galaxy (BCG) in Abell 85 (Holm 15A) was obtained using the Gemini Multi Object Spectrograph. These data were taken with the aim of deriving an accurate surface brightness profile of the BCG of Abell 85, in particular, its central region. The new Gemini data show clear evidence of a previously unreported nuclear emission that is evident as a distinct light excess in the central kiloparsec of the surface brightness profile. We find that the light profile is never flat nor does it present a downward trend toward the center of the galaxy. That is, the new Gemini data show a different physical reality from the featureless, "evacuated core" recently claimed for the Abell 85 BCG. After trying different models, we find that the surface brightness profile of the BCG of Abell 85 is best fit by a double Sérsic model.

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Section: Nuclear Emission and Nuclear Variabilitymentioning

confidence: 99%

The Abell 85 Bcg: A Nucleated, Coreless Galaxy

Madrid

Donzelli

2016

ApJ

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“…′′ 3 in both J 125 and H 160 stacks and hence seems to be resolved. Another possibility is that this object is an active galactic nucleus (AGN; see, e.g., Cohen et al 2006) at z 7.4, or a transient at a similar redshift. Without further data, it is difficult to determine its nature.…”

Section: Samplementioning

confidence: 99%

PROBING VERY BRIGHT END OF GALAXY LUMINOSITY FUNCTION AT z ≳ 7 USING HUBBLE SPACE TELESCOPE PURE PARALLEL OBSERVATIONS

Yan

Zamojski

et al. 2011

ApJ

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We report the first results from the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble Space Telescope to do deep imaging along a large number of random sightlines. To date, our analysis includes 26 widely separated fields observed by the Wide Field Camera 3, which amounts to 122.8 arcmin 2 in total area. We have found three bright Y 098 -dropouts, which are candidate galaxies at z 7.4. One of these objects shows an indication of peculiar variability and its nature is uncertain. The other two objects are among the brightest candidate galaxies at these redshifts known to date (L > 2L * ). Such very luminous objects could be the progenitors of the high-mass Lyman break galaxis (LBGs) observed at lower redshifts (up to z ∼ 5). While our sample is still limited in size, it is much less subject to the uncertainty caused by "cosmic variance" than other samples because it is derived using fields along many random sightlines. We find that the existence of the brightest candidate at z ≈ 7.4 is not well explained by the current luminosity function (LF) estimates at z ≈ 8. However, its inferred surface density could be explained by the prediction from the LFs at z ≈ 7 if it belongs to the high-redshift tail of the galaxy population at z ≈ 7.

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“…If the event occurs in the outskirts of the host galaxy or is not detected in X-ray, the variable object is likely to be shock breakout. 22 And the deep UV, optical, and infrared imaging 22 Some low-luminosity AGN at high redshift can not be detected even in deep X-ray data (Sarajedini et al 2006;Cohen et al 2006; data are also useful for excluding the possibility of stars. Furthermore, if the field is included in the field of view of γ-ray telescope (e.g., Swift/BAT, Gehrels et al 2004), an alert of GRB can be used for ruling out a possibility of GRB.…”

Section: Identification Of Shock Breakoutmentioning

confidence: 99%

Shock Breakout in Type Ii Plateau Supernovae: Prospects for High-Redshift Supernova Surveys

Tominaga

Morokuma

Блинников

et al. 2011

ApJS

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Shock breakout is the brightest radiative phenomenon in a supernova (SN) but is difficult to be observed owing to the short duration and X-ray/ultraviolet (UV)-peaked spectra. After the first observation from the rising phase reported in 2008, its observability at high redshift is attracting enormous attention. We perform multigroup radiation hydrodynamics calculations of explosions for evolutionary presupernova models with various main-sequence masses M MS , metallicities Z, and explosion energies E. We present multicolor light curves of shock breakout in Type II plateau SNe, being the most frequent core-collapse SNe, and predict apparent multicolor light curves of shock breakout at various redshifts z. We derive the observable SN rate and reachable redshift as functions of filter x and limiting magnitude m x,lim by taking into account an initial mass function, cosmic star formation history, intergalactic absorption, and host galaxy extinction. We propose a realistic survey strategy optimized for shock breakout. For example, the g ′ -band observable SN rate for m g ′ ,lim = 27.5 mag is 3.3 SNe degree −2 day −1 and a half of them locates at z ≥ 1.2. It is clear that the shock breakout is a beneficial clue to probe high-z core-collapse SNe. We also establish ways to identify shock breakout and constrain SN properties from the observations of shock breakout, brightness, time scale, and color. We emphasize that the multicolor observations in blue optical bands with ∼ hour intervals, preferably over ≥ 2 continuous nights, are essential to efficiently detect, identify, and interpret shock breakout.

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Clues to Active Galactic Nucleus Growth from Optically Variable Objects in the Hubble Ultra Deep Field

Cited by 23 publications

References 24 publications

The Abell 85 Bcg: A Nucleated, Coreless Galaxy

The Abell 85 Bcg: A Nucleated, Coreless Galaxy

PROBING VERY BRIGHT END OF GALAXY LUMINOSITY FUNCTION AT z ≳ 7 USING HUBBLE SPACE TELESCOPE PURE PARALLEL OBSERVATIONS

Shock Breakout in Type Ii Plateau Supernovae: Prospects for High-Redshift Supernova Surveys

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