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The mid-infrared spectroscopic analysis of a flux-limited sample of galaxies with fv(24um) > 10 mJy is presented. Sources observed are taken from the Spitzer First Look Survey (FLS) catalog and from the NOAO Deep Wide-Field Survey region in…

Astrophysics · Physics 2011-02-11 Daniel W. Weedman , James R. Houck

We present the results of a systematic search for outbursts in the narrow positron annihilation line on various time scales (5x10^4 - 10^6 s) based on the SPI/INTEGRAL data obtained from 2003 to 2008. We show that no outbursts were detected…

High Energy Astrophysical Phenomena · Physics 2015-05-18 S. Tsygankov , E. Churazov

Infrared observations can probe photometric variability across the full evolutionary range of young stellar objects (YSOs), from deeply embedded protostars to pre-main-sequence stars with dusty disks. We present 3-8 micron light curves…

We present a detailed study of the 2017 eruption of the classical nova ASASSN-17pf (LMCN 2017-11a), which is located in the Large Magellanic Cloud, including data from AAVSO, ASAS-SN, SALT, SMARTS, SOAR, and the Neil Gehrels \textit{Swift}…

[Abridged] We have discovered 10 periodic X-ray sources from the 1 Ms Chandra ACIS observation of the Limiting Window (LW), a low extinction region (A_V~3.9) at 1.4 Deg south of the Galactic center. The observed periods (~1.3 to 3.4 hours)…

High Energy Astrophysical Phenomena · Physics 2015-05-27 JaeSub Hong , Maureen van den Berg , Jonathan E. Grindlay , Mathieu Servillat , Ping Zhao

Ground-based and satellite observations have hinted at the existence of polar stratospheric clouds (PSCs) with relatively high optical depths, even if optical depth values are hard to come by. This study documents a type II PSC observed…

Atmospheric and Oceanic Physics · Physics 2015-05-14 Vincent Noel , Albert Hertzog , Hélène Chepfer

Approximately 0.01 % of all Si IV 1394 A spectra sampled in 2013 and 2014 by the Interface Region Imaging Spectrograph (IRIS) have IRIS burst profiles. However, these events are not evenly distributed across datasets with 19.31 % of these…

Solar and Stellar Astrophysics · Physics 2022-12-14 C. J. Nelson , L. Kleint

Long and short gamma-ray bursts are traditionally associated with galactic environments, where circumburst densities are small or moderate (few to hundreds of protons per cubic cm). However, both are also expected to occur in the disks of…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Davide Lazzati , Gustavo Soares , Rosalba Perna

Accreting white dwarfs (WDs) constitute a significant fraction of the hard X-ray sources detected by the INTEGRAL observatory. Most of them are magnetic Cataclysmic Variables (CVs) of the intermediate polar (IP) and polar types, but the…

Ionized outflows in Active Galactic Nuclei (AGN) are thought to influence their nuclear and local galactic environment. However, the distance of the outflows with respect to the central engine is poorly constrained, which limits our…

High Energy Astrophysical Phenomena · Physics 2017-11-22 Junjie Mao , J. S. Kaastra , M. Mehdipour , A. J. J. Raassen , Liyi Gu , J. M. Miller

Fast radio bursts are extragalactic, sub-millisecond radio impulses of unknown origin [1,2]. Their dispersion measures, which quantify the observed frequency-dependent dispersive delays in terms of free-electron column densities,…

High Energy Astrophysical Phenomena · Physics 2019-07-16 Vikram Ravi

The mechanism causing breaks in the radial surface brightness distribution of spiral galaxies is not yet well known. Despite theoretical efforts, there is not a unique explanation for these features and the observational results are not…

In the delayed explosion scenario of core-collapse supernovae (SNe), the accretion phase shows pronounced convective overturns and a low-multipole hydrodynamic instability, the standing accretion shock instability (SASI). These effects…

High Energy Astrophysical Phenomena · Physics 2014-11-21 Tina Lund , Andreas Marek , Cecilia Lunardini , Hans-Thomas Janka , Georg Raffelt

We review recent 3D high resolution numerical HD and MHD studies of a multi-component and multi-phase ISM. The computational grid was chosen large enough in the disk to represent typical ISM gas patterns, and in the halo to include the full…

Astrophysics · Physics 2007-05-23 Dieter Breitschwerdt , Miguel A. de Avillez

Large scale outflows of different gas phases are ubiquitous in the host galaxies of active galactic nuclei (AGN). Despite their many differences, they share a common property - they all contain dust. The dust is carried with the outflow,…

Astrophysics of Galaxies · Physics 2018-11-07 Dalya Baron , Hagai Netzer

We report the detection of the Diffuse Interstellar Bands (``$DIBs$'') in the optical spectra of seven far-infrared-selected starburst galaxies. The $\lambda$6283.9 \AA and $\lambda$ 5780.5 \AA features are detected with equivalent widths…

Astrophysics · Physics 2009-10-31 Timothy M. Heckman , Matthew D. Lehnert

AIMS. In this work we explore the possibility of using the fast expansion of a Type Ia supernova photosphere to detect extra-galactic ISM column density variations on spatial scales of ~100 AU on time scales of a few months. METHODS. We…

Astrophysics of Galaxies · Physics 2015-05-18 F. Patat , N. L. J. Cox , J. Parrent , D. Branch

The first generation of stars, Population III (Pop III), is believed to be massive, with some potentially having masses in the range 140 M$_\odot$ to 270 M$_\odot$ and capable of exploding as a pair-instability supernova (PISN). Such events…

Astrophysics of Galaxies · Physics 2026-05-13 Aron Kordt , Simon C. O. Glover , Ralf S. Klessen

We argue that the outbursts of the FU Orionis stars occur on timescales which are much longer than expected from the standard disc instability model with \alpha_{c} \gtrsim 10^{-3}. The outburst, recurrence, and rise times are consistent…

Astrophysics · Physics 2009-11-10 O. M. Matthews , R. Speith , G. A. Wynn

AIMS: We investigated fast optical variability of selected nova-like cataclysmic variables observed by TESS satellite. We searched for break frequencies (f_b) in the corresponding power density spectra (PDS). The goal is to study whether…

Solar and Stellar Astrophysics · Physics 2024-10-11 A. Dobrotka , J. Magdolen , D. Janikova
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