Related papers: Pressure Shift and Gravitational Red Shift of Balm…
Gravitational redshift is a fundamental parameter that allows us to determine the mass-to-radius ratio of compact stellar objects, such as black holes, neutron stars, and white dwarfs (WDs). In the X-ray spectra of the close binary system,…
The origin of magnetic fields in white dwarfs (WDs) remains mysterious. Magnetic WDs are traditionally associated with field strengths $\gtrsim1\,\mathrm{MG}$, set by the sensitivity of typical spectroscopic magnetic field measurements.…
We present an analysis of the star-formation rates (SFRs) and dust attenuation properties of star-forming galaxies at $2.7\leq z<6.5$ drawn from the Cosmic Evolution Early Release Science (CEERS) Survey. Our analysis is based on {\it…
Disk polarization at (sub)millimeter wavelengths is being revolutionized by ALMA observationally, but its origin remains uncertain. Dust scattering was recently recognized as a potential contributor to polarization, although its basic…
Murphy et al. (2003a, MNRAS, 345, 609) claim to find evidence of cosmological variations of the fine structure constant $\alpha$ in the spectra of intervening QSO absorption line systems. We find that this result is affected by systematic…
The DA white dwarfs in the Sloan Digital Sky Survey, as analyzed in the papers for Data Releases 1 and 4, show an increase in surface gravity towards lower effective temperatures below 11500 K. We study the various possible explanations of…
We report the first detailed spectroscopic observations of the recently identified intermediate polar RXJ0028.8+5917/V709 Cas. We discovered that the system shows significant EW ~ (2-4)A broad absorptions, affecting the Balmer lines from…
White dwarfs (WDs) can be used as laboratories to test strong gravity and high-density regimes, once their equation of state is not so uncertain as the one of neutron stars. This makes them also a useful tool to constrain dark-matter…
White dwarfs (WDs), as the remnants of low to intermediate-mass stars, provide a unique opportunity to explore the interplay between quantum mechanical degeneracy pressure and gravitational forces under extreme conditions. In this study, we…
The Swarm satellites fly at altitudes that at polar latitudes are generally assumed to onlycontain currents that are aligned with the local magnetic field. Therefore, disturbances along the main field direction are mainly signatures of…
We explore the dependence of dust attenuation, as traced by the $\rm H_{\alpha}/\rm H_{\beta}$ Balmer decrement, on galactic properties by using a large sample of SDSS spectra. We use both Partial Correlation Coefficients (PCC) and Random…
Gravitational waves have been shown to provide new constraints on gravitational theories beyond general relativity (GR), especially in the strong field regime. Gravitational wave signals from galactic double white dwarfs, expected to be…
The frequency shift of spectral lines from astronomical objects is most often explained by the Doppler Effect arising in relative motion and the broadening of a particular line is supposed to depend on the absolute temperature, pressure or…
We investigate the instability of layer pseudospin paramagnetic (PSP) state to the formation of pseudospin density wave (PSDW) in two-dimensional (2D) electron bilayers, analogous to the formation of Overhauser spin density wave (SDW) in a…
Dust attenuation of an inclined galaxy can cause additional asymmetries in observations, even if the galaxy has a perfectly symmetric structure. {Taking advantage of the integral field spectroscopic data observed by the SDSS-IV MaNGA…
We report the discovery of spectroscopic variations in the magnetic DBA white dwarf SDSS J091016.43+210554.2. Follow-up time-resolved spectroscopy at the Apache Point Observatory (APO) and the MMT show significant variations in the H…
In this study, we investigate the influence of an admixed fermionic dark matter (DM) component on the equilibrium structure of white dwarfs (WDs), with particular emphasis on the effects of varying the DM particle mass ($m_{\rm DM}$) and DM…
Using a large sample of quasar spectra from the SDSS, we examine the composite spectral trends of quasars as functions of both redshift and luminosity, independently of one another. Aside from the well known Baldwin effect (BE) -- the…
Measurements of the Hubble parameter from the distance ladder are in tension with indirect measurements based on the cosmic microwave background (CMB) data and the inverse distance ladder measurements at 3-4 $\sigma$ level. We consider…
Wind-driving in asymptotic giant branch (AGB) stars is commonly attributed to a two-step process. First, matter in the stellar atmosphere is levitated by shock waves, induced by stellar pulsation, and second, this matter is accelerated by…