A5039488415- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Geophysics and Sensor Technology
- Black Holes and Theoretical Physics
- Astrophysics and Star Formation Studies
- Relativity and Gravitational Theory
University of Nevada, Reno
2022-2024
Owing to their quiet evolutionary histories, nearby dwarf galaxies (stellar masses $M_\star \lesssim 3 \times 10^9 M_\odot$) have the potential teach us about mechanism(s) that 'seeded' growth of supermassive black holes, and also how first stellar mass holes formed interacted with environments. Here, we present high spatial-resolution observations three in X-ray (Chandra), optical/near-infrared (Hubble Space Telescope), radio (Karl G. Jansky Very Large Array). These were previously...
Abstract Ultraluminous X-ray sources (ULXs) were once largely believed to be powered by super-Eddington accretion onto stellar-mass black holes, although in some rare cases, ULXs also serve as potential candidates for (sub-Eddington) intermediate-mass holes. However, a total of eight have now been confirmed neutron stars, thanks observed pulsations, and may act contaminants the radio/X-ray selection Here, we present first comprehensive radio study seven known star using new archival data...
We present ultraviolet spectroscopy covering the Ly$\alpha$ + N V complex of six candidate low-redshift ($0.9 < z 1.5$) weak emission-line quasars (WLQs) based on observations with Hubble Space Telescope. The original systematic searches for these puzzling Type 1 intrinsically broad emission lines revealed an $N \approx 100$ WLQ population from optical high-redshift ($z > 3$) quasars, defined by a rest-frame equivalent width (EW) threshold $< 15.4$ \r{A}. Identification lower-redshift...
Abstract We present the first near-IR spectroscopy and joint analyses of multiwavelength observations for SDSS J082747.14+425241.1, a dust-reddened, weak broad emission-line quasar (WLQ) undergoing remarkable broad-absorption line (BAL) transformation. The systemic redshift is more precisely measured to be z = 2.070 ± 0.001 using H β compared 2.040 0.003 Mg ii from literature, signifying an extreme blueshift 2140 530 km s −1 relative . Using -based single-epoch scaling relation with...
The supermassive black holes ($M_{\rm BH} \sim 10^{6}$$-$$10^{10}~M_\odot$) that power luminous active galactic nuclei (AGNs), i.e., quasars, generally show a correlation between thermal disk emission in the ultraviolet (UV) and coronal hard X-rays. In contrast, some "massive" (mBHs; $M_{\rm 10^{5}$$-$$10^{6}~M_\odot$) low-mass galaxies present curious X-ray properties with radiative output up to 100$\times$ weaker than expected. To examine this issue, we new archival 10 GHz Very Large Array...
Abstract The supermassive black holes ( M BH ∼ 10 6 –10 ⊙ ) that power luminous active galactic nuclei (AGNs), i.e., quasars, generally show a correlation between thermal disk emission in the ultraviolet (UV) and coronal hard X-rays. In contrast, some “massive” (mBHs; 5 low-mass galaxies present curious X-ray properties with radiative output up to 100× weaker than expected. To examine this issue, we pilot study incorporating Very Large Array radio observations of sample 18...
We present near-infrared spectroscopy of ten weak emission-line quasars (WLQs) at redshifts $z\sim2$, obtained with the Palomar 200-inch Hale Telescope. WLQs are an exceptional population type 1 that exhibit or no broad emission lines in ultraviolet (e.g., C IV $\lambda 1549$ line), and they display remarkable X-ray properties. derive H$\beta$-based single-epoch virial black-hole masses (median value $\rm 1.7 \times 10^{9} M_{\odot}$) Eddington ratios $0.5)$ for our sources. confirm previous...
Abstract We present near-infrared spectroscopy of 10 weak emission-line quasars (WLQs) at redshifts z ∼ 2, obtained with the Palomar 200 inch Hale Telescope. WLQs are an exceptional population type 1 that exhibit or no broad emission lines in ultraviolet (e.g., C iv λ 1549 line), and they display remarkable X-ray properties. derive H β -based single-epoch virial black hole masses (median value 1.7 × 9 M ⊙ ) Eddington ratios 0.5) for our sources. confirm previous finding WLQ lines, as a major...
Ultraluminous X-ray sources (ULXs) were once largely believed to be powered by super-Eddington accretion onto stellar-mass black holes, although in some rare cases, ULXs also serve as potential candidates for (sub-Eddington) intermediate mass holes. However, a total of eight have now been confirmed neutron stars, thanks observed pulsations, and may act contaminants radio/X-ray selection Here we present the first comprehensive radio study seven known star using new archival data from Karl G....