All posts under category "Astrophysics / Astro-Ph.GA"
The Cepheus B (CepB) molecular cloud and a portion of the nearby CepOB3b OB association, one of the most active regions of star formation within 1 kpc, have been observed with the IRAC detector on board the Spitzer Space Telescope. The goals are to study protoplanetary disk evolution and processes o
The anomalous chemical abundances and the structure of the Edgewood-Kuiper belt observed in the solar system constrain the initial mass and radius of the star cluster in which the sun was born to $Msimeq500$ to 3000 msun and $Rsimeq 1$ to 3 pc. When the cluster dissolved the siblings of the sun disp
A generic prediction in the paradigm of weakly interacting dark matter is the production of relativistic particles from dark matter pair-annihilation in regions of high dark matter density. Ultra-relativistic electrons and positrons produced in the center of the Galaxy by dark matter annihilation sh
We combine IR, optical and X-ray data from the overlapping, 9.3 square degree NOAO Deep Wide-Field Survey (NDWFS), AGN and Galaxy Evolution Survey (AGES), and XBootes Survey to measure the X-ray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral ty
The emission from Sgr A*, the supermassive black hole in the Galactic Center, shows order of magnitude variability ('flares') a few times a day that is particularly prominent in the near-infrared (NIR) and X-rays. We present a time-dependent model for these flares motivated by the hypothesis that di
We study merger histories of dark-matter haloes in a suite of N-body simulations that span different cosmological models. The simulated cases include the up-to-date WMAP5 cosmology and other test cases based on the Einstein-deSitter cosmology with different power spectra. We provide a robust fitting
The discovery of the youngest Galactic supernova remnant (SNR) G1.9+0.3 has allowed a look at a stage of SNR evolution never before observed. We analyze the 50 ks Chandra observation with particular regard to spectral variations. The very high column density ($N_H sim 6 times 10^{22}$ cm$^{-2}$) imp
We report the discovery from Hubble Space Telescope ACS images of an extended globular cluster, denoted by Scl-dE1 GC1, in the Sculptor Group dwarf Elliptical galaxy Scl-dE1 (Sc22). The distance of the dE is determined as 4.3 +/- 0.25 Mpc from the I magnitude of the tip of the red giant branch in th
We present results of three-dimensional, fully nonlinear MHD simulations of a large-scale magnetic field evolution in a barred galaxy. The model does not take into consideration the dynamo process. We find that the obtained magnetic field configurations are highly similar to the observed maps of the
The bright, nearby, recently discovered supernova SN2010jl is a member of the rare class of relatively luminous Type~IIn events. Here we report archival HST observations of its host galaxy UGC5189A taken roughly 10yr prior to explosion, as well as early-time optical spectra of the SN. The HST images
We report on the search for 0.1-10 GeV emission from magnetars in 17 months of Fermi Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently-known magnetars is found. The most stringent upper limits to date on their persistent emission in the
We present the first to date three-dimensional high-resolution hydrodynamical simulation tracing the non-equilibrium ionization evolution (using the Eborae Atomic and Molecular Plasma Emission Code - E(A+M)PEC) of the Local Bubble and Loop I superbubbles embedded in a turbulent supernova-driven inte
To understand Galactic objects that emits GeV-TeV emission, a spatial correlation study between the Fermi bright source catalog and TeV source population was carried out in Tam et al. (2010), finding that a significant number of very high-energy (VHE; E >100 GeV) sources are also emitting at GeV ene
Numerical integration of the differential equations of light propagation in the Schwarzschild metric shows that in some extreme situations relevant for practical observations (e.g. for Gaia) the well-known standard post-Newtonian formula for the boundary problem has an error up to 16 muas. The aim o
We investigate the theoretical and observational implications of the acceleration of protons and heavier nuclei in supernova remnants (SNRs). By adopting a semi-analytical technique, we study the non-linear interplay among particle acceleration, magnetic field generation and shock dynamics, outlinin
We present the SINS survey with SINFONI of high redshift galaxies. With 80 objects observed and 63 detected, SINS is the largest survey of spatially resolved gas kinematics, morphologies, and physical properties of star-forming galaxies at z~1-3. We describe the selection of the targets, the observa
E(A+M)PEC traces the ionization structure, cooling and emission spectra of plasmas. It is written in OpenCL, runs in NVIDIA Graphics Processor Units and can be coupled to any HD or MHD code to follow the dynamical and thermal evolution of any plasma in, e.g., the interstellar medium (ISM).
Variability is one of the hallmarks of Active Galactic Nuclei. The Burst Alert Telescope onboard of Swift, with its homogeneous coverage of the sky is a formidable tool to study variability at hard X-rays. We present here the analysis of the 1-month binned Swift/BAT lightcurves of the 20 brightest A
We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar PSR J0030+0451 with the Large Area Telescope (LAT) on the emph{Fermi} Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR J0030+0451 the second millisecond pulsar to be detected in gamma-rays
Open clusters have long been used to illuminate both stellar evolution and Galactic evolution. The oldest clusters, though rather rare, can reveal the chemical and nucleosynthetic processes early in the history of the Galaxy. We have studied two turn-off stars in the old, metal-rich open cluster, NG
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