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Time-domain astronomy with swift, fermi and lobster

Proceedings of the International Astronomical Union 2011年第S285期7卷 41-46页

作者： Gehrels, Neil Barthelmy, Scott D. Cannizzo, John K. Astroparticle Physics Laboratory NASA Goddard Space Flight Center Greenbelt MD 20771 United States Astroparticle Physics Laboratory CRESST Goddard Space Flight Center Greenbelt MD 20771 United States

The dynamic transient gamma-ray sky is revealing many interesting results, largely due to findings by Fermi and Swift. The list includes new twists on gamma-ray bursts (GRBs), a GeV flare from a symbiotic star, GeV flares from the Crab Nebula, high-energy emission from novae and supernovae, and, within the last year, a new type of object discovered by Swift - a jetted tidal disruption event. In this review we present highlights of these exciting discoveries. A new mission concept called Lobster is also described;it would monitor the X-ray sky at order-of-magnitude higher sensitivity than current missions can. © 2012 International Astronomical Union.

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Searching for kaluza-klein dark matter signatures in the lat electron flux

Searching for kaluza-klein dark matter signatures in the lat...

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5th International Workshop on Science with the New Generation High Energy Gamma-Ray Experiments - The Light of the Dark: Solving the Mysteries of the Universe, SciNeGHE 2007

作者： Moiseev, A.A. Baltz, Edward A. Ormes, J.F. Titarchuk, L.G. CRESST and Astroparticle Physics Laboratory NASA GSFC Greenbelt United States KIPAC Menlo Park United States University of Denver Denver United States NRL Washington United States

We present here the prospects for the GLAST Large Area Telescope (LAT) detection of the signature of the lightest Kaluza-Klein particle (LKP). It decays by direct annihilation into electron-positron pairs that may be detectable in the high energy electron flux. We discuss the LAT capability for detecting the high energy (20 GeV - 1 TeV) cosmic ray electron flux and we analyze the LAT sensitivity to detect LKP-produced electrons for various particle masses. We include an analysis of the diffusive propagation of the electrons in the galaxy.

关键词： Electrons

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Comparing small and large SEP events and the role of flares and shocks

Comparing small and large SEP events and the role of flares ...

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30th International Cosmic Ray Conference, ICRC 2007

作者： Cane, H.V. Richardson, I.G. Von Rosenvinge, T.T. Astroparticle Physics Laboratory NASA/GSFC Greenbelt MD 20771 United States University of Tasmania Hobart TAS 7001 Australia CRESST and University of Maryland College Park MD 20742 United States

We have surveyed the properties and solar associations of the 300 >20 MeV proton events that were observed near Earth in 1997-2005. About 20% have the properties of so-called "impulsive" events that are considered to arise from acceleration in flares. Another 31% of the events are the large, well studied, "gradual" events, that are considered to comprise only shock accelerated particles. The remaining events are often ignored but comprise ~50% of the events. We find that these events have intermediate properties such that there is a continuum of properties from the smallest to the largest events. It thus seems unlikely that there are two classes of fundamentally different events. Rather, there are two processes, one related to flares and one to coronal mass ejection shocks. As solar events become more energetic, shock acceleration becomes more important because of increasing CME energy. However, the flare characteristics also change so that flare particles in energetic events have different abundances from those in small events. We illustrate this for an impulsive event and another small event.

关键词： Cosmology

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Gamma-ray astronomy technology needs

Gamma-ray astronomy technology needs

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62nd International Astronautical Congress 2011, IAC 2011

作者： Gehrels, N. Cannizzo, J.K. Astroparticle Physics Laboratory NASA/Goddard Space Flight Center Greenbelt MD 20771 United States Astroparticle Physics Laboratory JCA/CRESST/UMBC NASA/Goddard Space Flight Center Greenbelt MD 20771 United States

ISBN: (纸本)9781618398055

In recent decades γ-ray observations have become a valuable tool for studying the universe. Progress made in diverse areas such as GRBs, nucleosynthesis, and AGNs has complimented and enriched our astrophysical understanding in many ways. We present an overview of current and future planned space γ-ray missions and discussion technology needs for the next generation of space γ-ray instruments.

关键词： Gamma rays

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Detecting the EBL Attenuation of Blazars with GLAST

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AIP Conference Proceedings 2007年第1期921卷 359-360页

作者： Luis C. Reyes CRESST — Astroparticle Physics Laboratory NASA/GSFC Greenbelt MD 20771 Department of Physics University of Maryland College Park MD 20742

The Large Area Telescope (LAT) on board GLAST (Gamma‐ray Large Area Space Telescope) due for launch in late 2007 will study the gamma‐ray sky in the energy range 20 MeV to >300 GeV. GLAST‐LAT’s improved sensitivity with respect to previous missions will increase the number of known blazars from about 100 to thousands, with redshifts up to z ∼3–5. Since gamma rays with energy above 10 GeV interact via pair‐production with photons from the Extragalactic Background Light (EBL), the systematic attenuation of GLAST‐detected blazars as a function of redshift would constitute and effective and unique probe to the optical‐UV EBL density and its evolution over cosmic history. Based on the GLAST‐LAT instrument performance, simulations of expected blazar populations attenuated by EBL have been performed.

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Swift Observations of Gamma Ray Bursts

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AIP Conference Proceedings 2008年第1期968卷 3-8页

作者： Neil Gehrels Swift Team Astroparticle Physics Laboratory NASA/GSFC Greenbelt MD 20771 USA

Since its launch on 20 November 2004, the Swift mission is detecting ∼100 gamma‐ray bursts (GRBs) each year, and immediately (within ∼90 s ) starting X‐ray and UV/optical observations of the afterglow. It has already collected an impressive database including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows, and rapid follow‐up by other observatories notified through the GCN. The detection of X‐ray afterglows have been found to have complex temporal shapes including tails emission from the prompt phase and bright flares. X‐ray afterglows from short bursts has led to accurate localizations. It is found that they can occur in non‐star forming galaxies or regions, whereas long GRBs are strongly concentrated within star forming regions. This is consistent with the NS merger model. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z∼5–6, are approaching the era of reionization. Ground‐based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to much greater distance than other techniques. The localization of GRB 060218 to a nearby galaxy, and association with SN 2006aj, added a valuable member to the class of GRBs with detected supernova. The prospects for future progress are excellent give the >10 year orbital lifetime of the Swift satellite.

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The hard X-ray emission from scorpius X-1 as seen by INTEGRAL

The hard X-ray emission from scorpius X-1 as seen by INTEGRA...

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7th INTEGRAL Workshop - An INTEGRAL View of Compact Objects, INTEGRAL 2008

作者： Sturner, Steven J. Shrader, Chris R. CRESST Astroparticle Physics Laboratory NASA/GSFC Greenbelt MD 20771 United States Center for Space Science and Technology University of Maryland Baltimore County Baltimore MD 21250 United States Universities Space Research Association Columbia MD 21044 United States

We present the results of our hard X-ray and gamma-ray study of the LMXB Sco X-1 utilizing INTEGRAL data as well as contemporaneous RXTE PCA data. We have investigated the hard X-ray spectral properties of Sco X-1 including the nature of the high-energy, nonthermal component and its possible correlations with the location of the source on the soft X-ray color-color diagram. We find that Sco X-1 follows two distinct spectral tracks when the 20-60 keV count rate is >130 counts/second. One state is a hard state which exhibits a significant high-energy, pow-erlaw tail to the lower energy thermal spectrum. The other state shows a much less significant high-energy component. We found suggestive evidence for a correlation of these hard and soft high-energy states with the position of Sco X-1 on the low-energy X-ray color-color diagram. We have searched for similar behavior in 2 other Z sources: GX 17+2 and GX 5-1 with negative results.

关键词： Gamma rays

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Measuring 10-1000 GeV cosmic ray electrons with GLAST/LAT

Measuring 10-1000 GeV cosmic ray electrons with GLAST/LAT

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30th International Cosmic Ray Conference, ICRC 2007

作者： Moiseev, Alexander Ormes, Jonathan F. Moskalenko, Igor V. CRESST and Astroparticle Physics Laboratory NASA/GSFC Greenbelt MD 20771 United States Universities Space Research Association Columbia MD 21044 United States University of Denver Denver CO 80208 United States HEPL and KIPAC Stanford University Stanford CA 94305 United States

We present here the capabilities of the GLAST Large Area Telescope to detect cosmic ray high-energy (HE) electrons in the energy range from 10 GeV to 1 TeV. We also discuss the science topics that can be investigated with HE electron data and quantify the results with LAT instrument simulations. The science topics include CR propagation, calibration of the IC gamma-ray model, testing hypotheses regarding the origin of HE energy cosmic-ray electrons, searching for any signature of Kaluza Klein Dark Matter annihilation, and measuring the HE electron anisotropy. We expect to detect ~ 107 electrons above 20 GeV per year of LAT operation.

关键词： Germanium alloys

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The bulk motion of gas in the core of the Centaurus galaxy cluster

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Nature 2025年第8050期638卷 365-369页

作者： Majumder, Anwesh Hosogi, Kokoro Sun, Ming Plšek, Tomáš Werner, Norbert Kondo, Marie Zhuravleva, Irina Yukita, Mihoko Yoshida, Tessei Yoneyama, Tomokage Yaqoob, Tahir Yamauchi, Shigeo Yamauchi, Makoto Yamasaki, Noriko Y. Yamaoka, Kazutaka Yamaguchi, Hiroya Yamada, Shinya Yamada, Satoshi Williams, Brian J. Watanabe, Shin Vink, Jacco Uno, Shinichiro Ueda, Yoshihiro Uchiyama, Hideki Uchida, Yuusuke Uchida, Nagomi Uchida, Hiroyuki Tsuru, Takeshi G. Tsunemi, Hiroshi Tsujimoto, Masahiro Tsuboi, Yohko Trigo, María Díaz Terashima, Yuichi Terada, Yukikatsu Tashiro, Makoto Tanimoto, Atsushi Tanaka, Takaaki Tamura, Keisuke Tamagawa, Toru Takeo, Mai Takahashi, Hiromitsu Szymkowiak, Andrew Suzuki, Hiromasa Smith, Randall Simionescu, Aurora Shidatsu, Megumi Seta, Hiromi Sawada, Makoto Sato, Toshiki Sato, Kosuke Pottschmidt, Katja Porter, Frederick Scott Plucinsky, Paul Petre, Robert Paltani, Stephane Ota, Naomi Okajima, Takashi Ogorzalek, Anna Ogawa, Shoji Odaka, Hirokazu Noda, Hirofumi Nobukawa, Masayoshi Nobukawa, Kumiko Ness, Jan-Uwe Nakazawa, Kazuhiro Nakajima, Hiroshi Mushotzky, Richard Murakami, Hiroshi Mukai, Koji Mori, Koji Mizuno, Tsunefumi Mizumoto, Misaki Mitsuishi, Ikuyuki Miller, Jon M. Miller, Eric D. Mernier, François McNamara, Brian McCammon, Dan Matsushita, Kyoko Matsumoto, Hironori Markevitch, Maxim Maeda, Yoshitomo Loewenstein, Michael Leutenegger, Maurice Kubota, Aya Kohmura, Takayoshi Kobayashi, Shogo Kitamoto, Shunji Kilbourne, Caroline Kelley, Richard Kanemaru, Yoshiaki Katsuda, Satoru Kara, Erin Kallman, Timothy Kaastra, Jelle Ishisaki, Yoshitaka Ishikawa, Kumi Ishida, Manabu Ichinohe, Yuto Hornschemeier, Ann Hodges-Kluck, Edmund Hell, Natalie Hayashi, Takayuki Hayashi, Katsuhiro Hatsukade, Isamu Hamaguchi, Kenji Hagino, Kouichi Guainazzi, Matteo Gu, Liyi García, Javier A. Gallo, Luigi Furuzawa, Akihiro Fukushima, Kotaro Fukazawa, Yasushi Fujita, Yutaka Fujimoto, Ryuichi Foster, Adam Ezoe, Yuichiro Eguchi, Satoshi Enoto, Teruaki Eckert, Dominique Eckart, Megan E. Ebisawa, Ken Dotani, Tadayasu Done, Chris Department of Physics Ehime University Matsuyama Japan Department of Astronomy University of Maryland College Park MD United States NASA/Goddard Space Flight Center Greenbelt MD United States Center for Research and Exploration in Space Science and Technology NASA/GSFC (CRESST II) Greenbelt MD United States Department of Physics University of Tokyo Tokyo Japan Department of Physics Technion Haifa Israel Center for Space Science and Technology University of Maryland Baltimore County Baltimore MD United States Center for Astrophysics | Harvard-Smithsonian Cambridge MA United States Lawrence Livermore National Laboratory Livermore CA United States Department of Astronomy University of Michigan Ann Arbor MI United States SRON Netherlands Institute for Space Research Leiden Netherlands Centre for Extragalactic Astronomy Department of Physics University of Durham Durham United Kingdom Institute of Space and Astronautical Science (ISAS) Japan Aerospace Exploration Agency (JAXA) Kanagawa Japan Department of Physics Kyoto University Kyoto Japan Department of Economics Kumamoto Gakuen University Kumamoto Japan Department of Physics Tokyo Metropolitan University Tokyo Japan Department of Physics Hiroshima University Hiroshima Japan Department of Physics Fujita Health University Toyoake Japan Department of Astronomy and Physics Saint Mary’s University Halifax Nova Scotia Canada Cahill Center for Astronomy and Astrophysics California Institute of Technology Pasadena CA United States European Space Agency (ESA) European Space Research and Technology Centre (ESTEC) Noordwijk Netherlands Faculty of Engineering University of Miyazaki Miyazaki Japan RIKEN Nishina Center Saitama Japan Leiden Observatory University of Leiden Leiden Netherlands Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology Cambridge MA United States Department of Physics Saitama University Saitama Japan Department of Physics Rikkyo Universi

Galaxy clusters contain vast amounts of hot ionized gas known as the intracluster medium (ICM). In relaxed cluster cores, the radiative cooling time of the ICM is shorter than the age of the cluster. However, the absence of line emission associated with cooling suggests heating mechanisms that offset the cooling, with feedback from active galactic nuclei (AGNs) being the most likely source^1,2. Turbulence and bulk motions, such as the oscillating (‘sloshing’) motion of the core gas in the cluster potential well, have also been proposed as mechanisms for heat distribution from the outside of the core^3,4. Here we present X-ray spectroscopic observations of the Centaurus galaxy cluster with the X-Ray Imaging and Spectroscopy Mission satellite. We find that the hot gas flows along the line of sight relative to the central galaxy, with velocities from 130 km s⁻¹ to 310 km s⁻¹ within about 30 kpc of the centre. This indicates bulk flow consistent with core gas sloshing. Although the bulk flow may prevent excessive accumulation of cooled gas at the centre, it could distribute the heat injected by the AGN and bring in thermal energy from the surrounding ICM. The velocity dispersion of the gas is found to be only ≲120 km s⁻¹ in the core, even within about 10 kpc of the AGN. This suggests that the influence of the AGN on the surrounding ICM motion is limited in the cluster. © The Author(s), under exclusive licence to Springer Nature Limited 2025.

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Can 59Ni synthesized in OB associations decay to 59Co before being accelerated to cosmic-ray energies?

Can 59Ni synthesized in OB associations decay to 59Co before...

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30th International Cosmic Ray Conference, ICRC 2007

作者： Binns, W.R. Cummings, A.C. De Nolfo, G.A. Israel, M.H. Leske, R.A. Mewaldt, R.A. Von Rosenvinge, T.T. Stone, E.C. Wiedenbeck, M.E. Washington University St. Louis MO 63130 United States California Institute of Technology Pasadena CA 91125 United States CRESST Astroparticle Physics Laboratory NASA/GSFC Greenbelt MD 20771 United States NASA Goddard Space Flight Center Greenbelt MD 20771 United States Jet Propulsion Laboratory California Institute of Technology Pasadena CA 91109 United States

Observations from the Cosmic Ray Isotope Spectrometer (CRIS) aboard nasa's Advanced Composition Explorer (ACE) have shown that all relevant galactic cosmic-ray isotopic ratios measured are consistent with an OB-association origin of galactic cosmic rays (GCRs). Additionally CRIS measurements of the isotopic abundances of 59Ni and 59Co have shown that the 59Ni has completely decayed into 59Co, indicating a delay of >105 years between nucleosynthesis and acceleration. However, it has been suggested that shocks generated from high-velocity Wolf-Rayet winds in the OB-association environment must accelerate nuclei synthesized in nearby core-collapse supernovae on a time scale short compared to the 59Ni half-life of 7.6x104 years. If this were the case, it would imply that OB associations could not be the source of most galactic cosmic rays. In this paper, we describe the OB-association history and environment and show that the time scales for acceleration are such that most 59Ni should be expected to decay naturally in that setting, strengthening the argument that OB associations are the likely source of a substantial fraction of galactic cosmic rays.

关键词： Isotopes

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