Search Publications
Galaxy And Mass Assembly (GAMA): the dependence of star formation on surface brightness in low-redshift galaxies
Bremer, M. N.; Holwerda, B. W.; De Propris, R. +5 more
The star-formation rate in galaxies is well known to correlate with stellar mass (the 'star-forming main sequence'). Here, we extend this further to explore any additional dependence on galaxy surface brightness, a proxy for stellar mass surface density. We use a large sample of low-redshift (z ≤ 0.08) galaxies from the Galaxy And Mass Assembly su…
Exploring the Emission Mechanisms of Mrk 180 with Long-term X-Ray and γ-Ray Data
Gupta, Nayantara; Mondal, Sandeep Kumar; Das, Saikat
Markarian (Mrk) 180 is a BL Lacertae object located at a redshift of 0.045 and is a potential candidate for high-energy cosmic-ray acceleration. We have analyzed the Fermi Large Area Telescope (Fermi-LAT) γ-ray data of Mrk 180 collected over a period of 12.8 yr and found no significant enhancement in the flux from the long-term γ-ray light curve. …
3D stellar motion in the axisymmetric Galactic potential and the e-z resonances
Barros, Douglas A.; Michtchenko, Tatiana A.
Context. The full phase-space information on the kinematics of a huge number of stars provided by Gaia Data Release 3 increases the demand for a better understanding of the 3D stellar dynamics.
Aims: In this paper, we investigate the possible regimes of motion of stars in the axisymmetric approximation of the Galactic potential, applying a 3D…
Supernovae Origin for the Low-latitude Intermediate-velocity Arch and the North Celestial Pole Loop
Jorissen, A.; Verschuur, G. L.; Schmelz, J. T. +1 more
Supernova explosions attributed to the unseen companion in several binary systems identified by the Third Gaia Data Release (Gaia DR3) may be responsible for a number of well-known and well-studied features in the radio sky, including the low-latitude intermediate-velocity (LLIV) arch and the north celestial pole (NCP) loop. Slices from the longit…
A Scattered Star Group in the Orion A Region of the Milky Way
Kovaleva, Dana; Sapozhnikov, Sergei; Vereshchagin, Sergei +4 more
Using Gaia DR3 data, we identified an extended a ~60 pc group of stars sharing common motion but scattered in space, including from 150 to 300 probable members, named Group V. It can be associated with a group identified by Getman et al. (2019) and by Jerabkova et al. (2019) as a relic of a gas filament, traced by the mutual position of stars afte…
Timescale of Stellar Feedback-driven Turbulence in the ISM: A Deep Dive into UGC 4305
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Cohen, Roger E. +3 more
Understanding the interplay of stellar feedback and turbulence in the interstellar medium (ISM) is essential to modeling the evolution of galaxies. To determine the timescales over which stellar feedback drives turbulence in the ISM, we performed a spatially resolved, multiwavelength study of the nearby star-forming dwarf galaxy UGC 4305. As indic…
New red giants in NGC 6791 and NGC 6819 using Kepler superstamps
Hekker, S.; Covelo-Paz, A.; Themeßl, N. +1 more
Context. Stars that are members of stellar clusters are assumed to be formed at the same time and place from material with the same initial chemical composition. These additional constraints on the ensemble of cluster stars make these stars suitable as benchmarks.
Aims: We aimed (1) to identify previously unknown red giants in the open cluste…
Solar radio bursts observations by Egypt- Alexandria CALLISTO spectrometer: First results
Kozarev, K.; Minta, F. N.; Nozawa, S. I. +2 more
The newly installed CALLISTO spectrometer, hosted by the Department of Space Environment, Institute of Basic and Applied Sciences- EJUST, commenced operation on August 14, 2021. The system contains a cross dipole long-wavelength array antenna with high sensitivity to monitor solar radio transients. Its antenna was strategically positioned and appe…
Discovery of an extended G giant chromosphere in the 2019 eclipse of γ Per
Schmitt, J. H. M. M.; Fridlund, M.; Schröder, K. -P. +3 more
The November 2019 eclipse of γ Per was a rare opportunity to seek evidence for a chromosphere of the G8 giant, hitherto suspected but not detected. Twenty-nine years after the only other observed eclipse, we aim to find chromospheric absorption in the strong Ca II H&K lines, and to determine its column densities and scale height. Using the Tel…
Search for DA White Dwarf Binary Candidates from LAMOST DR7
Zhao, Gang; Zhao, Jing-Kun; Wang, Liang +4 more
We obtained spectroscopy data for 761 Degenerate A (DA)white dwarfs (WDs) with multiple LAMOST observations. The radial velocity (RV) of each spectrum was calculated using the cross-correlation function method (CCF), and 60 DA WD binary candidates were selected based on the variation of the RV. Then, the atmosphere parameter Teff, logg, and the ma…