Search Publications
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. X. Optical Variability Characteristics
Ho, Luis C.; Bian, Wei-Hao; Zhang, Zhi-Xiang +11 more
We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns, including our ongoing campaign of monitoring super-Eddington accreting massive black holes (BHs). This sample covers a large range of BH mass ({M}\bullet ={10}6{--9} {M}⊙ ), dimensionless accreti…
Probing cosmic dawn: modelling the assembly history, SEDs, and dust content of selected z ∼ 9 galaxies
Ellis, Richard S.; Laporte, Nicolas; Devriendt, Julien +2 more
The presence of spectroscopically confirmed Balmer breaks in galaxy spectral energy distributions (SEDs) at z > 9 provides one of the best probes of the assembly history of the first generations of stars in our Universe. Recent observations of the gravitationally lensed source, MACS 1149_JD1 (JD1), indicate that significant amounts of star form…
Quiescent Galaxy Size and Spectroscopic Evolution: Combining HSC Imaging and Hectospec Spectroscopy
Geller, Margaret J.; Utsumi, Yousuke; Damjanov, Ivana +3 more
We explore the relationships between size, stellar mass, and average stellar population age (indicated by D n 4000 indices) for a sample of ∼11,000 intermediate-redshift galaxies from the SHELS spectroscopic survey (Geller et al. 2014) augmented by high-resolution Subaru Telescope Hyper Suprime-Cam imaging. In the redshift interval 0.1…
Quasar Sightline and Galaxy Evolution (QSAGE) survey - I. The galaxy environment of O VI absorbers up to z = 1.4 around PKS 0232-04
Cullen, F.; Bower, R. G.; Tejos, N. +8 more
We present the first results from a study of O VI absorption around galaxies at z < 1.44 using data from a near-infrared grism spectroscopic Hubble Space Telescope Large Programme, the Quasar Sightline and Galaxy Evolution (QSAGE) survey. QSAGE is the first grism galaxy survey to focus on the circumgalactic medium at z ∼ 1, providing a blind su…
Evolutionary phases of merging clusters as seen by LOFAR
Brunetti, G.; Shimwell, T. W.; Cassano, R. +13 more
Massive, merging galaxy clusters often host giant, diffuse radio sources that arise from shocks and turbulence; hence, radio observations can be useful for determining the merger state of a cluster. In preparation for a larger study, we selected three clusters - Abell 1319, Abell 1314, and RXC J1501.3+4220 (Z7215) - making use of the new LOFAR Two…
NuStar Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk
Ho, Luis C.; Younes, George; Yuan, Feng +5 more
We report the analysis of simultaneous XMM-Newton+Nuclear Spectroscopic Telescope Array (NuSTAR) observations of two low-luminosity active galactic nuclei (LLAGNs), NGC 3998 and NGC 4579. We do not detect any significant variability in either source over the ∼3 day length of the NuSTAR observations. The broadband 0.5-60 keV spectrum of NGC 3998 is…
The Period-Luminosity Relations of Red Supergiants in M33 and M31
Yang, Ming; Jiang, Bi-Wei; Gao, Jian +1 more
Based on previously selected preliminary samples of red supergiants (RSGs) in M33 and M31, the foreground stars and luminous asymptotic giant branch stars are further excluded, which leads to the samples of 717 RSGs in M33 and 420 RSGs in M31. With the time-series data from the Intermediate Palomar Transient Factory survey spanning nearly 2000 day…
Interpretation of Departure from the Broad-line Region Scaling in Active Galactic Nuclei
Czerny, Bożena; Panda, Swayamtrupta; Du, Pu +7 more
Most results of the reverberation monitoring of active galaxies showed a universal scaling of the time delay of the Hβ emission region with the monochromatic flux at 5100 Å, with very small dispersion. Such a scaling favored the dust-based formation mechanism of the broad-line region (BLR). Recent reverberation measurements showed that actually a …
Stellar binaries that survive supernovae
Kochanek, C. S.; Belczynski, K.; Auchettl, K.
The number of binaries containing black holes (BH) or neutron stars (NS) depends critically on the fraction of binaries that survive supernova (SN) explosions. We searched for surviving star plus remnant binaries in a sample of 49 supernova remnants (SNR) containing 23 previously identified compact remnants and three high-mass X-ray binaries (HMXB…
The H I velocity function: a test of cosmology or baryon physics?
Obreschkow, Danail; Lagos, Claudia del P.; Elahi, Pascal J. +3 more
Accurately predicting the shape of the H I velocity function (VF) of galaxies is regarded widely as a fundamental test of any viable dark matter model. Straightforward analyses of cosmological N-body simulations imply that the Λ cold dark matter (ΛCDM) model predicts an overabundance of low circular velocity galaxies when compared to observed H I …