Search Publications
Spiral density-wave structure parameters in the solar neighbourhood derived from longitudinal velocities of Gaia EDR3 OB stars: 3D approach
Mróz, Przemek; Gedalin, Michael; Jiang, Ing-Guey +2 more
Distances and transverse along the Galactic longitude velocities vl of 2640 Gaia EDR3 O-B2 stars of Xu et al. within 2.5 kpc from the Sun and 250 pc from the Galactic plane with relative distance and velocity accuracies of <10 and <50 per cent are selected. Under the assumption of spiral density waves, both Galactic differential r…
Stellar Populations in type Ia supernova host galaxies at intermediate-high redshift: Star formation and metallicity enrichment histories
Galbany, L.; Mollá, M.; Gomes, J. M. +5 more
We present a summary of our project that studies galaxies hosting type Ia supernova (SN Ia) at different redshifts. We present Gran Telescopio de Canarias (GTC) optical spectroscopy of six SN Ia host galaxies at redshift z ~ 0.4-0.5. They are joined to a set of SN Ia host galaxies at intermediate-high redshift, which include galaxies from surveys …
Probing the parameters of the intergalactic medium using quasars
Morris, Simon L.; Fumagalli, Michele; Gatuzz, Efrain +1 more
We continue our series of papers on intergalactic medium (IGM) tracers using quasi-stellar objects (QSOs), having examined gamma-ray bursts (GRBs) and blazars in earlier studies. We have estimated the IGM properties of hydrogen column density ($\mathit {N}\small {\rm HXIGM}$), temperature, and metallicity using XMM-Newton QSO spectra over a large …
Effect of the solar wind on the nature of arbitrary amplitude ion-acoustic solitary waves in Venus' upper ionosphere
Fichtner, H.; Lazar, M.; El-Shafeay, N. A. +5 more
Observations suggest that at altitudes of 1000-2000 km the interaction between the solar wind and Venus' ionospheric plasma leads to ion-acoustic waves (IAWs) formation. For studying this hypothesis, a suitable hydrodynamic model relying on the observational data from Pioneer Venus Orbiter (PVO) and Venus Express (VEX) is developed. It consists of…
Investigation of rocket effect in bright-rimmed clouds using Gaia EDR3
Ojha, D. K.; Maheswar, G.; Saha, Piyali +2 more
Bright-rimmed clouds (BRCs) are excellent laboratories to explore the radiation-driven implosion mode of star formation because they show evidence of triggered star formation. In our previous study, BRC 18 has been found to accelerate away from the direction of the ionizing H II region because of the well-known 'Rocket Effect'. Based on the assump…
J01020100-7122208: an accreted evolved blue straggler that was not ejected from a supermassive black hole
Hawkins, Keith; Jofré, Paula; Prieto, Jose L. +3 more
J01020100-7122208 is a star whose origin and nature still challenges us. It was first believed to be a yellow supergiant ejected from the Small Magellanic Cloud, but it was more recently claimed to be a red giant accelerated by the Milky Way's central black hole. In order to unveil its nature, we analysed photometric, astrometric, and high-resolut…
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$\lo…
CHANG-ES XXIX: the sub-kpc nuclear bubble of NGC 4438
Bregman, Joel N.; Beck, Rainer; Wang, Q. Daniel +8 more
Active galactic nucleus (AGN) bubbles could play an important role in accelerating high-energy cosmic rays (CRs) and galactic feedback. Only in nearby galaxies could we have high enough angular resolution in multiwavelengths to study the sub-kpc environment of the AGN, where the bubbles are produced and strongly interact with the surrounding inter…
Far-ultraviolet investigation into the galactic globular cluster M30 (NGC 7099): I. Photometry and radial distributions
Zurek, David R.; Kroupa, Pavel; Long, Knox S. +4 more
We present a far-ultraviolet (FUV) study of the globular cluster M30 (NGC 7099). The images were obtained using the Advanced Camera for Surveys (ACS/SBC, F150LP, FUV) and the Wide Field Planetary Camera 2 (WFPC2, F300W, UV) which were both onboard the Hubble Space Telescope. The FUV - UV colour-magnitude diagram (CMD) shows a main sequence (MS) tu…
X-ray spectral and timing analysis of the Compton Thick Seyfert 2 galaxy NGC 1068
Stalin, C. S.; Marchesi, S.; Parker, M. L. +2 more
We present the timing and spectral analysis of the Compton Thick Seyfert 2 active galactic nuclei NGC 1068 observed using NuSTAR and XMM-Newton. In this work for the first time we calculated the coronal temperature ($\rm {kT_{e}}$) of the source and checked for its variation between the epochs if any. The data analysed in this work comprised of (a…