Search Publications
Constraining Quasar Feedback from Analysis of the Hydrostatic Equilibrium of the Molecular Gas in Their Host Galaxies
Ho, Luis C.; Bauer, Franz E.; Treister, Ezequiel +4 more
We investigate the kinematics and dynamics of the molecular and ionized gas in the host galaxies of three Palomar-Green quasars at low redshifts, benefiting from the archival millimeter-wave interferometric and optical integral field unit data. We study the kinematics of both cold molecular and hot ionized gas by analyzing the CO and Hα data cubes…
Double-edged Sword: The Influence of Tidal Interaction on Stellar Activity in Binaries
Fang, Min; Wang, Song; Han, Henggeng +4 more
Using the LAMOST DR7 low-resolution spectra, we carried out a systematic study of stellar chromospheric activity in both single and binary stars. We constructed a binary sample and a single-star sample, mainly using the binary belt and the main sequence in the Hertzsprung–Russell diagram, respectively. By comparing the S indices between single and…
BST1047+1156: A (Failing) Ultradiffuse Tidal Dwarf in the Leo I Group
Mihos, J. Christopher; Durrell, Patrick R.; McGaugh, Stacy S. +2 more
We use deep Hubble Space Telescope imaging to study the resolved stellar populations in BST1047+1156, a gas-rich, ultradiffuse dwarf galaxy found in the intragroup environment of the Leo I galaxy group. While our imaging reaches approximately two magnitudes below the tip of the red giant branch at the Leo I distance of 11 Mpc, we find no evidence …
Recurrent Coronal Mass Ejections and Their Geomagnetic Storms Association on 2012 January 19: Solar Surface to Upper Earth's Atmosphere Analyses
Minta, F. N.; Hassanin, A.; Shimeis, Amira +1 more
In this study, we have conducted an analysis of space weather disruptions that occurred on 19 January 2012. Our analysis identified three coronal mass ejections (CMEs), CME1, CME2, and CME3—which were ejected at 09:48:05 universal time (UT), 14:36:05 UT, and 16:12:06 UT, respectively. Nonrecurrent disturbances in space weather, such as geomagnetic…
The Temperature and Density of a Solar Flare Kernel Measured from Extreme-ultraviolet Lines of O IV
Young, Peter R.
Previously unexplored diagnostics of O IV in the extreme-ultraviolet region 260–280 Å are used to derive a temperature and density for a solar flare kernel observed on 2012 March 9 with the Extreme-ultraviolet Imaging Spectrometer on the Hinode satellite. Seven lines from the 2s2p 2–2s2p3s transition array between 271.99 and 272.31 Å ar…
A Comparative Study of Two Contrasting Cosmic-Ray Events Caused by Solar Eruptions from NOAA AR 12673 in 2017 September
Zhang, Shuang Nan; Zhang, Ping; Yu, Xiao Xia +3 more
Two major solar eruptions on AR 12673 produced a Forbush decrease (FD) event (reduction of cosmic rays) on 2017 September 8 and ground-level enhancement (GLE; enhancement of cosmic rays) on 2017 September 10. The occurrence of two contrasting cosmic-ray events within 2 days that are associated with two similar X-class solar flares (X9.3 and X8.2) …
An Outflow-driven Water Maser Associated with Positive Black Hole Feedback in the Dwarf Galaxy Henize 2–10
Darling, Jeremy; Reines, Amy E.; Momjian, Emmanuel +1 more
Henize 2–10 is a dwarf galaxy experiencing positive black hole (BH) feedback from a radio-detected low-luminosity active galactic nucleus. Previous Green Bank Telescope (GBT) observations detected a H2O "kilomaser" in Henize 2–10, but the low angular resolution (33″) left the location and origin of the maser ambiguous. We present new Ka…
X-Ray, UV, and Optical Observations of Proxima Centauri's Stellar Cycle
Slavin, Jonathan D.; do Nascimento, José-Dias; Saar, Steven H. +3 more
Proxima Cen (GJ 551; dM5.5e) is one of only about a dozen fully convective stars known to have a stellar cycle, and the only one to have long-term X-ray monitoring. A previous analysis found that X-ray and mid-UV observations, particularly two epochs of data from Swift, were consistent with a well-sampled ∼7 yr optical cycle seen in All Sky Automa…
An X-Ray Significantly Variable, Luminous, Type 2 Quasar at z = 2.99 with a Massive Host Galaxy
Marchesi, Stefano; Gilli, Roberto; Zhao, Xiurui +8 more
We present a comprehensive X-ray analysis and spectral energy distribution (SED) fitting of WISEA J171419.96+602724.6, an extremely luminous type 2 quasar at z = 2.99. The source was suggested as a candidate Compton-thick (column density N H > 1.5×1024 cm‑2) quasar by a short XMM-Newton observation in 2011. We r…
KM UMa: An Active Short-period Detached Eclipsing Binary in a Hierarchical Quadruple System
Meng, Fangbin; Zhu, Liying; Liu, Nianping +4 more
The first detailed photometric and spectroscopic analysis of the G-type eclipsing binary KM UMa is presented, which indicates that the system is a short-period detached eclipsing binary. The radial velocity curves were calculated using the cross-correlation function method based on Large Sky Area Multi-Object Fiber Spectroscopic Telescope, Sloan D…