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Catalog of short gamma-ray transients detected in the SPI/INTEGRAL experiment
Minaev, P. Yu.; Pozanenko, A. S.; Grebenev, S. A. +1 more
We analyzed the data obtained by the SPI telescope onboard the INTEGRAL observatory to search for short transient events with a duration from 1 ms to a few tens of seconds. An algorithm for identifying gamma-ray events against the background of a large number of charged particle interactions with the detector has been developed. The classification…
Probing the Large and Massive Circumgalactic Medium of a Galaxy at z ~ 0.2 using a Pair of Quasars
Muzahid, Sowgat
We present an analysis of two O VI absorbers at redshift z abs = 0.227, which were detected in the spectra of two closely spaced QSO sightlines (Q 0107-025A and B) and observed with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope. At the same redshift, the presence of a single bright (~1.2L sstarf) galaxy a…
Outflows from active galactic nuclei: the BLR-NLR metallicity correlation
Valls-Gabaud, David; Du, Pu; Hu, Chen +4 more
The metallicity of active galactic nuclei (AGNs), which can be measured by emission line ratios in their broad- and narrow-line regions (BLRs and NLRs), provides invaluable information about the physical connection between the different components of AGNs. From the archival data bases of the International Ultraviolet Explorer, the Hubble Space Tel…
Orbital apocenter is not a sufficient condition for HST/STIS detection of Europa's water vapor aurora
Nimmo, Francis; Saur, Joachim; Roth, Lorenz +4 more
We report far-ultraviolet observations of Jupiter's moon Europa taken by Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) in January and February 2014 to test the hypothesis that the discovery of a water vapor aurora in December 2012 by local hydrogen (H) and oxygen (O) emissions with the STIS originated from plume a…
Herschel celestial calibration sources. Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range
Pearson, Chris; Lim, Tanya; Linz, Hendrik +9 more
Celestial standards play a major role in observational astrophysics. They are needed to characterise the performance of instruments and are paramount for photometric calibration. During the Herschel Calibration Asteroid Preparatory Programme approximately 50 asteroids have been established as far-IR/sub-mm/mm calibrators for Herschel. The selected…
HESS J1640-465 - an exceptionally luminous TeV γ-ray supernova remnant
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +217 more
The results of follow-up observations of the TeV γ-ray source HESS J1640-465 from 2004 to 2011 with the High Energy Stereoscopic System (HESS) are reported in this work. The spectrum is well described by an exponential cut-off power law with photon index Γ = 2.11 ± 0.09stat ± 0.10sys, and a cut-off energy of E_c = 6.0^{+2.0}_…
Constraining topological defects with temperature and polarization anisotropies
Kunz, Martin; Liddle, Andrew R.; Lizarraga, Joanes +3 more
We analyze the possible contribution of topological defects to cosmic microwave anisotropies, both temperature and polarization. We allow for the presence of both inflationary scalars and tensors, and of polarized dust foregrounds that may contribute to or dominate the B-mode polarization signal. We confirm and quantify our previous statements tha…
Interferometric Follow-up of WISE Hyper-luminous Hot, Dust-obscured Galaxies
Tsai, Chao-Wei; Gelino, Christopher R.; Wright, Edward L. +10 more
The Wide-field Infrared Survey Explorer (WISE) has discovered an extraordinary population of hyper-luminous dusty galaxies that are faint in the two bluer passbands (3.4 µm and 4.6 µm) but are bright in the two redder passbands of WISE (12 µm and 22 µm). We report on initial follow-up observations of three of these hot, dus…
Quasi Periodic Oscillations in Blazars
Gupta, Alok C.
Here we report our recent discoveries of Quasi-Periodic Oscillations (QPOs) in blazars time series data in X-ray and optical electromagnetic bands. Any such detection can give important clue of the location and nature of the processes of emission mechanism. In the case of radio-quiet AGN, the detected QPOs are very likely to be associated with the…
Archival legacy investigations of circumstellar environments: overview and first results
Schneider, Glenn; Hines, Dean C.; Perrin, Marshall D. +12 more
We are currently conducting a comprehensive and consistent re-processing of archival HST-NICMOS coronagraphic surveys using advanced PSF subtraction methods, entitled the Archival Legacy Investigations of Circumstellar Environments program (ALICE, HST/AR 12652). This virtual campaign of about 400 targets has already produced numerous new detection…