Search Publications
Redshift-luminosity characterization of active galactic nucleus galaxies having obscuring dusty material using the spectral energy distribution from the X-ray to far-infrared
Gadallah, Kamel A. K.
The spectral energy distribution (SED) from the X-ray to far-IR is used to characterize active galactic nuclei (AGNs) having obscuring dusty material. A sample of 73 AGNs, with redshifts of z < 2.5, is subdivided based on the optical spectra into subgroups of type 1 and 2 AGNs and no-AGN. The X-CIGALE code is used to produce the SEDs of these g…
A NICER Viewing Angle on the Accretion Stream of Vela X-1
Behar, Ehud; Rahin, Roi
Vela X-1 is the archetypal eclipsing high-mass X-ray binary, composed of a neutron star (NS) accreting the B-star wind. It was observed by nearly all X-ray observatories, often multiple times, featuring a rich spectrum of variable emission lines. However, the precise origin of these lines in the binary system remains uncertain. We perform a system…
Detecting Long-period Variability in the SDSS Stripe 82 Standards Catalog
Ivezić, Željko; Ilić, Dragana; Kovačević, Andjelka B. +5 more
We report the results of a search for long-period (100 < P < 600 days) periodic variability in the SDSS Stripe 82 standards catalog. The SDSS coverage of Stripe 82 enables such a search because there are on average 20 observations per band in ugriz bands for about one million sources, collected over about 6 yr, with a faint limit of r ~ 22 m…
Jitter Radiation as an Alternative Mechanism for the Nonthermal X-Ray Emission of Cassiopeia A
Greco, Emanuele; Vink, Jacco; Ferrigno, Carlo +1 more
Synchrotron radiation from relativistic electrons is usually invoked as responsible for the nonthermal emission observed in supernova remnants. Diffusive shock acceleration is the most popular mechanism to explain the process of particles acceleration and within its framework a crucial role is played by the turbulent magnetic field. However, the s…
Exploring the Origin of Solar Energetic Electrons. I. Constraining the Properties of the Acceleration Region Plasma Environment
Jeffrey, Natasha L. S.; Pallister, Ross
Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect energetic electrons in interplanetary space. We examine if the plasma properties of an acceleration region (size, t…
Unveiling the chemical fingerprint of phosphorus-rich stars. I. In the infrared region of APOGEE-2
Masseron, Thomas; Hayes, Christian R.; Pignatari, Marco +4 more
Context The origin of phosphorus, one of the essential elements for life on Earth, is currently unknown. Prevalent models of Galactic chemical evolution (GCE) systematically underestimate the amount of P compared to observations, especially at low metallicities. The recently discovered P-rich ([P/Fe] ≳ 1.2 dex) and metal-poor ([Fe/H] ≃ −1.0 dex) g…
Revisiting multiwavelength data on the supersoft X-ray source CAL 83
D'Amico, F.; Jablonski, F.; Stecchini, P. E. +1 more
In this study, we revisit public data on the supersoft X-ray source CAL 83 in the Large Magellanic Cloud. A significant part of our analysis is focused on XMM-Newton X-ray observations, in which updated data reduction procedures and quality assessment were applied. We report on the capability of publicly available hot atmosphere models in describi…
The magnetically controlled ionopause boundary observed by LPW onboard MAVEN within magnetic pile-up region of Mars
Haider, S. A.; Prasad, K. Durga; Shah, Siddhi Y.
We have analysed plasma and magnetic field data obtained from 627 orbits of Mars Atmosphere and Volatile Evolution (MAVEN) that occurred during October 2014, April 2015, September 2017 and May 2018, when the spacecraft was crossing the magnetic pile-up boundary of Mars. Two broad peaks and a drop are observed in this magnetic field region. The mag…
The Environments around W Serpentis Systems: Independent Limits on System Masses and Extended Envelopes
Davidge, T. J.
Information extracted from the Gaia Data Release 3 is used to examine the stellar contents within projected separations of 10 pc from eight close binary systems that are either classical W Serpentis systems or related objects. The goal is to search for remnant star clusters or moving groups with proper motions that are similar to those of the bina…
A method of photometric data extraction for asteroids from time-domain surveys
Muinonen, Karri; Penttilä, Antti; Xiang, Yue +9 more
The lightcurves of asteroids are essential for determining their physical characteristics, including shape, spin, size, and surface composition. However, most asteroids are missing some of these basic physical parameters due to lack of photometric data. Although a few telescopes or surveys are specially designed for photometric lightcurve observat…