Search Publications
The Ultra-long Gamma-Ray Burst 111209A: The Collapse of a Blue Supergiant?
Piro, L.; D'Elia, V.; Cutini, S. +8 more
We present optical, X-ray and gamma-ray observations of GRB 111209A, observed at a redshift of z = 0.677. We show that this event was active in its prompt phase for about 25000 s, making it the longest burst ever observed. This rare event could have been detected up to z ~ 1.4 in gamma-rays. Compared to other long gamma-ray bursts (GRBs), GRB 1112…
A Correlation between Star Formation Rate and Average Black Hole Accretion in Star-forming Galaxies
Gorjian, Varoujan; Dey, Arjun; Alberts, Stacey +14 more
We present a measurement of the average supermassive black hole accretion rate (BHAR) as a function of the star formation rate (SFR) for galaxies in the redshift range 0.25 < z < 0.8. We study a sample of 1767 far-IR-selected star-forming galaxies in the 9 deg2 Boötes multi-wavelength survey field. The SFR is estimated using 250 &…
A Significantly Low CO Abundance toward the TW Hya Protoplanetary Disk: A Path to Active Carbon Chemistry?
Cleeves, L. Ilsedore; Bergin, Edwin A.; Qi, Chunhua +2 more
In this Letter we report the CO abundance relative to H2 derived toward the circumstellar disk of the T-Tauri star TW Hya from the HD (1 - 0) and C18O (2 - 1) emission lines. The HD (1 - 0) line was observed by the Herschel Space Observatory Photodetector Array Camera and Spectrometer whereas C18O (2 - 1) observati…
HerMES: Candidate Gravitationally Lensed Galaxies and Lensing Statistics at Submillimeter Wavelengths
Aussel, H.; Pérez-Fournon, I.; Ivison, R. J. +83 more
We present a list of 13 candidate gravitationally lensed submillimeter galaxies (SMGs) from 95 deg2 of the Herschel Multi-tiered Extragalactic Survey, a surface density of 0.14 ± 0.04 deg-2. The selected sources have 500 µm flux densities (S 500) greater than 100 mJy. Gravitational lensing is confirmed by fol…
CLASH: The Enhanced Lensing Efficiency of the Highly Elongated Merging Cluster MACS J0416.1-2403
Shu, X.; Zheng, W.; Moustakas, J. +21 more
We perform a strong lensing analysis of the merging galaxy cluster MACS J0416.1-2403 (M0416; z = 0.42) in recent CLASH/HST observations. We identify 70 new multiple images and candidates of 23 background sources in the range 0.7 <~ z phot <~ 6.14 including two probable high-redshift dropouts, revealing a highly elongated lens with…
A Tight Connection between Gamma-Ray Outbursts and Parsec-scale Jet Activity in the Quasar 3C 454.3
Strelnitski, Vladimir; Walker, Gary; McHardy, Ian M. +42 more
We analyze the multi-frequency behavior of the quasar 3C 454.3 during three prominent γ-ray outbursts: 2009 Autumn, 2010 Spring, and 2010 Autumn. The data reveal a repeating pattern, including a triple flare structure, in the properties of each γ-ray outburst, which implies similar mechanism(s) and location for all three events. The multi-frequenc…
The Ultraluminous X-Ray Sources NGC 1313 X-1 and X-2: A Broadband Study with NuSTAR and XMM-Newton
Hailey, Charles J.; Fabian, Andrew C.; Fürst, Felix +16 more
We present the results of NuSTAR and XMM-Newton observations of the two ultraluminous X-ray sources: NGC 1313 X-1 and X-2. The combined spectral bandpass of the two satellites enables us to produce the first spectrum of X-1 between 0.3 and 30 keV, while X-2 is not significantly detected by NuSTAR above 10 keV. The NuSTAR data demonstrate that X-1 …
Herschel-ATLAS: A Binary HyLIRG Pinpointing a Cluster of Starbursting Protoellipticals
Kneib, J. -P.; Valtchanov, I.; Ivison, R. J. +48 more
Panchromatic observations of the best candidate hyperluminous infrared galaxies from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z = 2.41 galaxies across an ≈100 kpc region—a cluster of starbursting protoellipticals. Via subarcsecond interferometric imaging we have measured acc…
The Formation of IRIS Diagnostics. I. A Quintessential Model Atom of Mg II and General Formation Properties of the Mg II h&k Lines
De Pontieu, B.; Leenaarts, J.; Carlsson, M. +2 more
NASA's Interface Region Imaging Spectrograph (IRIS) space mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager centered at Mg II k. Understanding the observations will require forward modeling of Mg II h&k line formation from three-dimen…
A WFC3/HST View of the Three Stellar Populations in the Globular Cluster NGC 6752
Anderson, J.; Grundahl, F.; Milone, A. P. +9 more
Multi-band Hubble Space Telescope photometry reveals that the main sequence, sub-giant, and the red-giant branch of the globular cluster NGC 6752 splits into three main components in close analogy with the three distinct segments along its horizontal branch stars. These triple sequences are consistent with three stellar groups: a stellar populatio…