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Investigating variations in the dust emissivity index in the Andromeda Galaxy
Smith, M. W. L.; Eales, S. A.; Marsh, K. A. +3 more
Over the past decade, studies of dust in the Andromeda Galaxy (M31) have shown radial variations in the dust emissivity index (β). Understanding the astrophysical reasons behind these radial variations may give clues about the chemical composition of dust grains, their physical structure, and the evolution of dust. We use 12CO(J = 1$\lo…
Substructure at High Speed. I. Inferring the Escape Velocity in the Presence of Kinematic Substructure
Necib, Lina; Lin, Tongyan
The local escape velocity provides valuable inputs to the mass profile of the galaxy, and requires understanding the tail of the stellar speed distribution. Following Leonard & Tremaine, various works have since modeled the tail of the stellar speed distribution as $\propto {({v}_{\mathrm{esc}}-v)}^{k}$ , where v esc is the escape v…
Double peak quasi-periodic pulsations in a circular-ribbon flare
Altyntsev, A. T.; Meshalkina, N. S.; Sych, R. A. +1 more
We study quasi-periodic pulsations (QPPs) during the impulsive phase of the C8.3 flare SOL2002-08-06T01:43. The shape of an extended 5.7 GHz source is similar to a tadpole with the head located above the region of a negative magnetic polarity, surrounded by positive polarity patches and with a remote tail source. The flare configuration includes b…
An Investigation on the Morphological and Mineralogical Characteristics of Posidonius Floor Fractured Lunar Impact Crater Using Lunar Remote Sensing Data
Salem, Imen Ben; Sharma, Manish; Kumaresan, P. R. +4 more
Lunar floor-fractured craters (FFCs) are a distinguished type of crater found on the surface of the Moon with radial, concentric, and/or polygonal fractures. In the present study, we selected the Posidonius FCC to explore the mineralogy, morphology and tectonic characteristics using remote sensing datasets. The Posidonius crater is vested with a w…
CHANG-ES XXIX: the sub-kpc nuclear bubble of NGC 4438
Bregman, Joel N.; Beck, Rainer; Wang, Q. Daniel +8 more
Active galactic nucleus (AGN) bubbles could play an important role in accelerating high-energy cosmic rays (CRs) and galactic feedback. Only in nearby galaxies could we have high enough angular resolution in multiwavelengths to study the sub-kpc environment of the AGN, where the bubbles are produced and strongly interact with the surrounding inter…
Deep Upper Limit on the Optical Emission during a Hard X-Ray Burst from the Magnetar SGR J1935+2154
Naletto, Giampiero; Burtovoi, Aleksandr; Mereghetti, Sandro +9 more
In 2021 September the magnetar SGR J1935+2154 entered a stage of burst/flaring activity in the hard X-ray band. On 2021 September 10, we observed SGR J1935+2154 with the fiber-fed fast optical photon counter IFI+Iqueye, mounted at the 1.22 m Galileo telescope in Asiago. During one of the IFI+Iqueye observing windows, a hard X-ray burst was detecte…
Ammonia characterisation of dense cores in the Rosette Molecular Cloud
Schneider, N.; Csengeri, T.; Motte, F. +5 more
Context. The Rosette molecular cloud complex is a well-known Galactic star-forming region with a morphology pointing towards triggered star formation. The distribution of its young stellar population and the gas properties point to the possibility that star formation is globally triggered in the region.
Aims: We focus on the characterisation …
Volume-limited sample of low-mass red giant stars, the progenitors of hot subdwarf stars. l. Sample selection and binary classification method
Uzundag, Murat; Jones, Matías I.; Bobrick, Alexey +3 more
Context. Current theory predicts that hot subdwarf binaries are produced from evolved low-mass binaries that have undergone mass transfer and drastic mass loss during either a common-envelope phase or a stable Roche-lobe overflow while on the red giant branch (RGB).
Aims: We perform a spectroscopic survey to find binary systems that include l…
Optical Cross-Match of SRG/eROSITA X-ray Sources Using the Deep Lockman Hole Survey as an Example
Gilfanov, M. R.; Belvedersky, M. I.; Bykov, S. D.
We present a method for the optical cross-match of sources detected in wide-field X-ray sky surveys. For this purpose, we have constructed and trained a neural network model to characterize the photometric attributes of the populations of optical counterparts of X-ray sources and optical field objects. The photometric information processing result…
Absolute parameters of four W UMa stars with extreme low mass ratios
Popov, Velimir A.; Petrov, Nikola I.
Photometric observations of four extreme low mass ratio W UMa binaries with wide total eclipses, and their absolute parameters are presented. The main results are as follows: (i) ASAS J015429+2042.8 is of A subtype while V755 Cep, VESPA V22 and GSC 02800-01387 are of W subtype; (ii) The mass ratios are close to the lower mass-ratio limit and can b…