Search Publications
A multiwavelength view of cooling versus AGN heating in the X-ray luminous cool-core of Abell 3581
Fabian, A. C.; Giacintucci, S.; Salomé, P. +12 more
We report the results of a multiwavelength study of the nearby galaxy group, Abell 3581 (z = 0.0218). This system hosts the most luminous cool core of any nearby group and exhibits active radio mode feedback from the supermassive black hole in its brightest group galaxy, IC 4374. The brightest galaxy has suffered multiple active galactic nucleus o…
The roles of star formation and AGN activity of IRS sources in the HerMES fields
Feltre, A.; Hatziminaoglou, E.; Hernán-Caballero, A. +16 more
In this work, we explore the impact of the presence of an active galactic nucleus (AGN) on the mid- and far-infrared (IR) properties of galaxies as well as the effects of simultaneous AGN and starburst activity in the same galaxies. To do this, we apply a multicomponent, multiband spectral synthesis technique to a sample of 250 µm selected g…
A near-infrared relationship for estimating black hole masses in active galactic nuclei
Peterson, Bradley M.; Elvis, Martin; Karovska, Margarita +4 more
Black hole masses for samples of active galactic nuclei (AGN) are currently estimated from single-epoch optical spectra using scaling relations anchored in reverberation mapping results. In particular, the two quantities needed for calculating black hole masses, namely the velocity and the radial distance of the orbiting gas are derived from the w…
Constraining the bright-end of the UV luminosity function for z ≈ 7-9 galaxies: results from CANDELS/GOODS-South
Wilkins, Stephen M.; Bunker, Andrew J.; Caruana, Joseph +3 more
The recent Hubble Space Telescope near-infrared imaging with the Wide-Field Camera #3 (WFC 3) of the Great Observatories Origins Deep Survey South (GOODS-S) field in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) programme covering nearly 100 arcmin2, along with already existing Advanced Camera for Surveys …
Young stellar population and ongoing star formation in the H II complex Sh2-252
Jose, Jessy; Samal, M. R.; Ojha, D. K. +7 more
In this paper, an extensive survey of the star-forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history for the first time. This complex is composed of five prominent embedded clusters associated with the subregions A, C, E, NGC 2175s an…
An extended main-sequence turn-off in the Small Magellanic Cloud star cluster NGC 411
Girardi, Léo; Chandar, Rupali; Marigo, Paola +8 more
Based on new observations with the Wide Field Camera 3 onboard the Hubble Space Telescope, we report the discovery of an extended main-sequence turn-off (eMSTO) in the intermediate-age star cluster NGC 411. This is the second case of an eMSTO being identified in a star cluster belonging to the Small Magellanic Cloud (SMC), after NGC 419. Despite t…
Resonant scattering in the Perseus Cluster: spectral model for constraining gas motions with Astro-H
Simionescu, A.; Sunyaev, R.; Sazonov, S. +6 more
X-ray spectra from cores of galaxy clusters can be strongly distorted by resonant scattering of line photons, affecting metal abundance and gas velocity measurements. We introduce simulated spectral models that take into account the resonant scattering effect, radial variations of thermodynamic properties of the hot gas, projection effects and sma…
The ACS LCID Project - VIII. The short-period Cepheids of Leo A
Skillman, Evan D.; Cole, Andrew A.; Tolstoy, Eline +9 more
We present the results of a new search for variable stars in the Local Group dwarf galaxy Leo A, based on deep photometry from the Advanced Camera for Surveys onboard the Hubble Space Telescope. We detected 166 bona fide variables in our field, of which about 60 per cent are new discoveries and 33 candidate variables. Of the confirmed variables, w…
HST/COS observations of a new population of associated QSO absorbers
Savage, B. D.; Narayanan, A.; Arav, N. +2 more
We present a sample of new population of associated absorbers, detected through Ne VIII λλ770, 780 absorption, in the Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) spectra of intermediate-redshift (0.45 < z < 1.21) quasars (QSOs). Our sample comprised of total 12 associated Ne VIII systems detected towards eight lines of sig…
Filling the gap: a new class of old star cluster.
Usher, C.; Spitler, L. R.; Strader, J. +5 more
It is not understood whether long-lived star clusters possess a continuous range of sizes and masses (and hence densities) or if rather, they should be considered as distinct types with different origins. Utilizing the Hubble Space Telescope to measure sizes and long exposures on the Keck 10 m telescope to obtain distances, we have discovered the …