Search Publications
On the Reliability of Photometric and Spectroscopic Tracers of Halo Relaxation
Gozaliasl, Ghassem; Zhoolideh Haghighi, Mohammad H.; Raouf, Mojtaba +2 more
We characterize the relaxation state of galaxy systems by providing an assessment of the reliability of the photometric and spectroscopic probe via the semianalytic galaxy evolution model. We quantify the correlations between the dynamical age of simuglated galaxy groups and popular proxies of halo relaxation in observation, which are mainly eithe…
OGLE-GAL-ACEP-091: The First Known Multi-mode Anomalous Cepheid
Soszyński, I.; Smolec, R.; Udalski, A. +12 more
Anomalous Cepheids (ACs) are metal-deficient, core-helium-burning pulsating stars with masses in the range 1.2-2.2 ${M}_{\odot }$ . Until recently, all known ACs were pure single-mode pulsators. The first candidate for an AC pulsating in more than one radial mode—OGLE-GAL-ACEP-091—was recently identified in the Milky Way based on the photometric d…
Revealing the Spectroscopic Variations of FU Orionis Object V960 Mon with High-resolution Spectroscopy
Honda, Satoshi; Itoh, Yoichi; Takagi, Yuhei +3 more
We present the results of the high-resolution spectroscopy of the FU Orionis-type star V960 Mon. The brightness of V960 Mon decreased continuously after the outburst was detected in 2014 November. During this dimming event, we carried out medium-resolution spectroscopic monitoring observations and found that the equivalent width of the absorption …
A New Microquasar Candidate in M83
Soria, Roberto; Blair, William P.; Long, Knox S. +2 more
Microquasars are neutron star or black hole X-ray binaries with jets. These jets can create bubbles of hot plasma shock ionized that can masquerade as peculiar supernova remnants (SNRs) in extragalactic surveys. To see if this is the case in the well-studied spiral galaxy M83, where one microquasar candidate (M83-MQ1) has already been identified, …
Type IIP Supernova Progenitors. II. Stellar Mass and Obscuration by the Dust in the Circumstellar Medium
Ray, Alak; Wagle, Gururaj A.
It has been well established from a variety of observations that red supergiants (RSGs) lose a lot of mass in stellar wind. Dust that has formed in this emitted gas over a few decades before core-collapse can lead to substantial extinction and obscure the intrinsic luminosity of the progenitor RSG. This may lead to a difficulty in determining the …
Young Stars near Cometary Globule CG 30 in the Tumultuous Gum Nebula
White, Russel J.; Yep, Alexandra C.
We have conducted a high-dispersion (R ∼ 34,000) optical spectroscopic study of 10 young stars near the cometary globule CG 30 in the Gum Nebula, a diffuse H II region home to at least 32 cometary globules. All 10 spectroscopically observed stars at the nebula's northern edge are of low mass (spectral types M4.5-K5), have broad Hα emission, and sh…
Spectroscopic Observations of High-speed Downflows in a C1.7 Solar Flare
Ding, M. D.; Li, Y.; Hong, Jie +2 more
In this paper, we analyze the high-resolution UV spectra for a C1.7 solar flare (SOL2017-09-09T06:51) observed by the Interface Region Imaging Spectrograph (IRIS). We focus on the spectroscopic observations at the locations where the cool lines of Si IV 1402.8 Å (∼104.8 K) and C II 1334.5/1335.7 Å (∼104.4 K) reveal significan…
Resolving the Nuclear Radio Emission from M32 with the Very Large Array
Li, Zhiyuan; Yuan, Feng; Sjouwerman, Loránt O. +3 more
The Local Group dwarf elliptical galaxy M32 hosts one of the nearest and most under-luminous supermassive black holes (SMBHs) ever known, offering a rare opportunity to study the physics of accreting SMBHs at the most quiescent state. Recent Very Large Array (VLA) observations detected a radio source at the nucleus of M32, which was suggested to b…
Spatially Resolved Study of Recombining Plasma in W49B Using XMM-Newton
Auchettl, Katie; Holland-Ashford, Tyler; Lopez, Laura A.
W49B is the youngest supernova remnant (SNR) to date that exhibits recombining plasma. The two prevailing theories of this overionization are rapid cooling via adiabatic expansion or through thermal conduction with an adjacent cooler medium. To constrain the origin of the recombining plasma in W49B, we perform a spatially resolved spectroscopic st…
On the Energetics of a Possible Relativistic Jet Associated with the Binary Neutron Star Merger Candidate S190425z
Mohan, S.; Saleem, M.; Resmi, L. +1 more
Advanced LIGO and Virgo (AdvLIGO/VIRGO) detectors reported the first binary neutron star merger candidate in the third observing run, S190425z, on 2019 April 25. A weak γ-ray excess was reported nearly coincidentally by the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite, which accidentally covered the entire localization regi…