Search Publications
HCG 57: Evidence for Shock-heated Intergalactic Gas from X-Rays and Optical Emission Line Spectroscopy
Zezas, Andreas; Appleton, P. N.; Vrtilek, Jan M. +5 more
We present Chandra and XMM-Newton X-ray observations of the compact group HCG 57, and optical integral field spectroscopy of the interacting galaxy pair HCG 57A/D. These two spiral galaxies recently suffered an off-axis collision with HCG 57D passing through the disk of A. We find evidence of a gas bridge linking the galaxies, containing ∼108…
Broadband γ-Ray Spectrum of Supernova Remnant Cassiopeia A
Liu, B.; Liu, Y.; Zhang, Yong +311 more
The core-collapse supernova remnant (SNR) Cassiopeia A (Cas A) is one of the brightest galactic radio sources with an angular radius of
Characterizing Stellar and Gas Properties in NGC 628: Spatial Distributions, Radial Gradients, and Resolved Scaling Relations
Kong, Xu; Esamdin, Ali; Zou, Hu +8 more
Building on our previous research involving multiwavelength data from UV to IR, we employ spectroscopic observations of ionized gas, as well as neutral hydrogen gas obtained from the Five-hundred Meter Aperture Spherical Telescope (FAST), to explore the intrinsic processes of star formation and chemical enrichment within NGC 628. Our analysis focu…
Equatorial Enhancement in the Dustiest OH/IR Stars in the Galactic Bulge
Goldman, Steven R.; Blommaert, Joris A. D. L.; van Loon, Jacco Th. +2 more
We have detected the 10 µm silicate feature and the 11.3 µm crystalline forsterite feature in absorption in 21 oxygen-rich asymptotic giant branch stars in the Galactic bulge. The depths of the 10 µm feature indicate highly obscured circumstellar environments. The additional crystalline features may suggest either an extended env…
Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud
Subramanian, S.; Subramaniam, A.; Dhanush, S. R.
We model the kinematics of the Small Magellanic Cloud (SMC) by analyzing the proper motions (PMs) from Gaia DR3 of nine different stellar populations, including young main-sequence (MS) stars (<2 Gyr), red giant branch stars, red clump stars, red giants with line-of-sight velocities, and three groups of star clusters. This analysis is carried o…
Signature of a Seyfert-like Component in Blazar 3C 273 and Its Reflection-based Explanation
Gaur, Haritma; Pal, Main; Anjum, Muhammad S. +4 more
We present the results of blazar 3C 273 from simultaneous observations obtained using the XMM-Newton and NuSTAR satellites during the period 2015–2019 in five epochs. When the spectra are modeled with a power law, significant residuals arise below ∼2 keV and in the energy range of 30–78 keV in NuSTAR data. Residuals in the lower energy band repres…
A Study of the Star Clusters' Population in the Giant Molecular Cloud G174+2.5
Carraro, Giovanni; Kirsanova, Maria S.; Sobolev, Andrej M. +3 more
We study the structure, interstellar absorption, color–magnitude diagrams (CMDs), kinematics, and dynamical state of embedded star clusters in the star-forming region associated with the giant molecular cloud G174+2.5. Our investigation is based on photometric data from the UKIDSS Galactic Plane Survey catalog and astrometric data from the Gaia DR…
Investigating the Lower Limit of Metallicity for the Galactic Thin Disk
Cui, Wenyuan; Hu, Guozhen; Shao, Zhengyi +1 more
We explore the metal-poor regime of the Galactic disk on the distribution of stars in the [α/M]–Vϕ plane, to identify the most metal-poor thin disk (MPTnD) stars belonging to the low-α sequence. Chemical abundances and velocities of sample stars are either taken or derived from APOGEE DR17 and Gaia DR3 catalogs. We find the existence of…
New Potential Ultracompact X-Ray Binaries for Space-based Gravitational-wave Detectors from a Low-mass Main-sequence Companion Channel
Liu, Jinzhong; Chen, Minghua
We investigate the formation and evolution of ultracompact X-ray binaries (UCXBs) using the COMPAS binary evolution code, starting from the zero-age main sequence (MS). Focusing on the low-mass MS companion channel, we simulate gravitational-wave (GW) signals from UCXBs with LEGWORK and evaluate their detectability by space-based observatories suc…
Red Stellar Populations and Dust Extinction toward W3
Martin, P. G.; Campbell, J. L.; Rahman, M. +2 more
We explore red stellar populations toward the W3 giant molecular cloud through the use of optical-to-infrared (IR) photometry and Gaia DR 3 data, simultaneously characterizing stellar content and properties of dust in the molecular medium. We use a Rayleigh–Jeans color excess method modified to de-redden stellar observations of both red giants (RG…