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We report results from HST/NICMOS 2 micron imaging polarimetry of the central region of Centaurus A. In the vicinity of the nucleus we observe a complex polarization structure which we explain by a combination of scattering of nuclear light…

Does the Galaxy contain sources of micro-FRB, lower energy events resembling the known FRB but detectable only at Galactic distances? The answer to this question is essential to determining the nature of FRB sources. At typical ($10$ kpc)…

High Energy Astrophysical Phenomena · Physics 2020-05-11 J. I. Katz

The probability of detecting a planetary companion of a lensing star during a microlensing event toward the Galactic center, averaged over all relevant event and galactic parameters, when the planet-star mass ratio $q=0.001$ has a maximum…

Astrophysics · Physics 2009-11-06 S. J. Peale

We report on Chandra X-ray observations of ASASSN-18tb/SN 2018fhw, a low luminosity Type Ia supernova that showed a H line in its optical spectrum. No X-ray emission was detected at the location of the SN. Upper limits to the luminosity of…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Vikram V. Dwarkadas

We investigate the possibility of detecting artificial lights from Proxima b's dark side by computing light curves from the planet and its host star. The two different scenarios we consider are artificial illumination with the same spectrum…

Earth and Planetary Astrophysics · Physics 2021-05-19 Elisa Tabor , Abraham Loeb

Due to their scarcity, microlensing events in the Galactic disk are of great interest and high-cadence photometric observations, supplemented by spectroscopic follow-up, are necessary for constraining the physical parameters of the lensing…

We present the analysis of emission lines in high-resolution optical spectra of the planet-host star Proxima Centauri (Proxima) classified as a M5.5V\@. We carry out the detailed analysis of observed spectra to get a better understanding of…

Solar and Stellar Astrophysics · Physics 2017-10-11 Ya. V. Pavlenko , A. Suarez Mascareno , R. Rebolo , N. Lodieu , V. J. S. Bejar , J. I. Gonzalez Hernandez

The Lyman-alpha emitters found at z=4.5 and 5.7 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in the Lyman-alpha line. Such lines can be produced by narrow-lined active galactic nuclei (AGNs) or by stellar…

Astrophysics · Physics 2009-11-07 S. Malhotra , J. X. Wang , J. E. Rhoads , T. M. Heckman , C. Norman

A new type of the THz laser is proposed. A coherent tera-hertz light is emitted through the backward Raman scattering between a visible light laser and a relativistic electron beam. The threshold conditions for the laser intensity and the…

Plasma Physics · Physics 2020-03-05 S. Son

The GALEX (Galaxy Evolution Explorer) spectroscopic survey mode, with a resolution of about 8 A in the FUV (1350 - 1750 A) and about 20 A in the NUV (1950 - 2750 A) is used for a systematic search of Ly-a emitting galaxies at low redshift.…

Proxima Centauri is our nearest stellar neighbor and one of the most well-studied stars in the sky. In 2016, a planetary companion was detected through radial velocity measurements. Proxima Centauri b has a minimum mass of 1.3 Earth masses…

Earth and Planetary Astrophysics · Physics 2021-10-27 Emily A. Gilbert , Thomas Barclay , Ethan Kruse , Elisa V. Quintana , Lucianne M. Walkowicz

We report a sensitive X-ray search for the proposed intermediate mass black hole (IMBH) in the massive Galactic cluster, Omega Centauri (NGC 5139). Combining Chandra X-ray Observatory data from Cycles 1 and 13, we obtain a deep (~291 ks)…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Daryl Haggard , Adrienne M. Cool , Craig O. Heinke , Roeland van der Marel , Haldan N. Cohn , Phyllis M. Lugger , Jay Anderson

The pointing directions of extensive air showers observed at the Pierre Auger Observatory were fitted within 3.1 degree with positions of the nearby active galactic nuclei from the Veron-Cetty and P. Veron catalog. The cosmic ray luminosity…

Astrophysics · Physics 2008-04-30 L. G. Dedenko , D. A. Podgrudkov , T. M. Roganova , G. F. Fedorova

We present the first radio observations of a sample of 13 optically and IR bright southern hemisphere classical Be stars made from the Australian Telescope Compact Array at 3.5cm and 6.3cm simultaneously. One star, delta Cen was detected at…

Astrophysics · Physics 2009-10-30 J S Clark , I A Steele , R P Fender

The existence of an axion-like particle (ALP) would induce anomalous scattering of light by light. This process can be probed at the Large Hadron Collider in central exclusive production of photon pairs in proton-proton collisions by…

High Energy Physics - Phenomenology · Physics 2018-08-01 Cristian Baldenegro , Sylvain Fichet , Gero von Gersdorff , Christophe Royon

Breakthrough Starshot is an initiative to prove ultra-fast light-driven nanocrafts, and lay the foundations for a first launch to Alpha Centauri within the next generation. Along the way, the project could generate important supplementary…

Instrumentation and Methods for Astrophysics · Physics 2018-12-11 Kevin L. G. Parkin

We report Keck LRIS observations of an arc-like background galaxy near the center of Abell 2152 (z=0.043), one of the three clusters comprising the Hercules supercluster. The background object has a redshift z=0.1423 and is situated 25…

Astrophysics · Physics 2009-10-31 John P. Blakeslee , Mark R. Metzger , Harald Kuntschner , Patrick Cote

The Kepler mission has led to the serendipitous discovery of a significant number of `super flares' - white light flares with energies between 10^33 erg and 10^36 erg - on solar-type stars. It has been speculated that these could be `freak'…

Solar and Stellar Astrophysics · Physics 2014-09-05 R. Wichmann , B. Fuhrmeister , U. Wolter , E. Nagel

The bright, nearby binary $\alpha$ Centauri provides an excellent laboratory for testing stellar evolution models, as it is one of the few stellar systems for which we have high-precision classical (mass, radius, luminosity) and…

Solar and Stellar Astrophysics · Physics 2018-09-19 M. Joyce , B. Chaboyer

We present the results of a search for clustering among the highest energy events detected by the surface detector of the Pierre Auger Observatory between 1 January 2004 and 31 August 2007. We analyse the autocorrelation function, in which…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Silvia Mollerach
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