Variability Studies of Multi-Wavelength Data from Gamma-Ray Blazars Mrk 421 and Mrk 501
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1. INTRODUCTION of the Beam (See, E.G., Mannheim 1993)
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by MURAL - Maynooth University Research Archive Library THE ASTROPHYSICAL JOURNAL, 511:149È156, 1999 January 20 ( 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. MEASUREMENT OF THE MULTI-TeV GAMMA-RAY FLARE SPECTRA OF MARKARIAN 421 AND MARKARIAN 501 F. KRENNRICH,1 S. D. BILLER,2 I. H. BOND,3 P. J. BOYLE,4 S. M. BRADBURY,3 A. C. BRESLIN,4 J. H. BUCKLEY,5 A. M. BURDETT,3 J. BUSSONS GORDO,4 D. A. CARTER-LEWIS,1 M. CATANESE,1 M. F. CAWLEY,6 D. J. FEGAN,4 J. P. FINLEY,7 J. A. GAIDOS,7 T. HALL,7 A. M. HILLAS,3 R. C. LAMB,8 R. W. LESSARD,7 C. MASTERSON,4 J. E. MCENERY,9 G. MOHANTY,1,10 P. MORIARTY,11 J. QUINN,12 A. J. RODGERS,3 H. J. ROSE,3 F. W. SAMUELSON,1 G. H. SEMBROSKI,6 R. SRINIVASAN,6 V. V. VASSILIEV,12 AND T. C. WEEKES12 Received 1998 July 22; accepted 1998 August 27 ABSTRACT The energy spectrum of Markarian 421 in Ñaring states has been measured from 0.3 to 10 TeV using both small and large zenith angle observations with the Whipple Observatory 10 m imaging telescope. The large zenith angle technique is useful for extending spectra to high energies, and the extraction of spectra with this technique is discussed. The resulting spectrum of Markarian 421 is Ðtted reasonably well by a simple power law: J(E) \ E~2.54B0.03B0.10 photons m~1 s~1 TeV~1, where the Ðrst set of errors is statistical and the second set is systematic. -
INTEGRAL View Of
INTEGRAL view of AGN Angela Maliziaa,∗, Sergey Sazonovb, Loredana Bassania, Elena Piana, Volker Beckmannc, Manuela Molinaa, Ilya Mereminskiyb, Guillaume Belangerd aOAS-INAF, Via P. Gobetti 101, 40129 Bologna, Italy bSpace Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117997 Moscow, Russia cInstitut National de Physique Nuclaire et de Physique des Particules (IN2P3) CNRS, Paris, France dESA/ESAC, Camino Bajo del Castillo, 28692 Villanueva de la Canada, Madrid, Spain Abstract AGN are among the most energetic phenomena in the Universe and in the last two decades INTEGRAL’s contribution in their study has had a significant impact. Thanks to the INTEGRAL extragalactic sky surveys, all classes of soft X-ray detected (in the 2-10 keV band) AGN have been observed at higher energies as well. Up to now, around 450 AGN have been catalogued and a conspicuous part of them are either objects observed at high-energies for the first time or newly discovered AGN. The high-energy domain (20-200 keV) represents an important window for spectral studies of AGN and it is also the most appropriate for AGN population studies, since it is almost unbiased against obscuration and therefore free of the limitations which affect surveys at other frequencies. Over the years, INTEGRAL data have allowed to characterise AGN spectra at high energies, to investigate their absorption properties, to test the AGN unification scheme and to perform population studies. In this review the main results are reported and INTEGRAL’s contribution to AGN science is highlighted for each class of AGN. Finally, new perspectives are provided, connecting INTEGRAL’s science with that at other wavelengths and in particular to the GeV/TeV regime which is still poorly explored. -
The Gamma-Ray Energy Spectrum of the Active Galaxy Markarian
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1997 The ag mma-ray energy spectrum of the active galaxy Markarian 421 Jeffrey Alan Zweerink Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Astrophysics and Astronomy Commons Recommended Citation Zweerink, Jeffrey Alan, "The ag mma-ray energy spectrum of the active galaxy Markarian 421 " (1997). Retrospective Theses and Dissertations. 11761. https://lib.dr.iastate.edu/rtd/11761 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in ^ewriter &ce, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missmg pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. -
Gamma Ray Astronomy Markarian
Gamma-Ray Emission by the BL Lac Markarian 501 Faculty Photo Student Photo Joshua Binks and Dr. David B. Kieda (credit: Salt Lake Tribune) Joshua Binks Department of Physics & Astronomy Dr. David B. Kieda Gamma Ray Astronomy Optical astronomy is the study of the heavens as they emit light, or the visible portion of the electromagnetic spectrum. Gamma-ray astronomy is the study of astrophysical sources that emit the most energetic form of electromagnetic radiation (ie: gamma-rays). High Energy gamma-rays are much too faint to be directly see with the human eye. Thus they are detected using arrays of large diameter (39 ft) mirrors and fast digitizing Image upper middle cameras which image the light emitted from the gamma-ray as it is absorbed in the Earth’s atmosphere. The VERITAS telescope array, located in Amado, Arizona, (see picture below) is the world’s most sensitive high- energy gamma-ray observatory. Since May 2009, I have worked with the VERITAS gamma-ray group at the University of Utah to observe sources of 2 high energy gamma rays as well as participate in the maintenance and upgrade of the telescopes (See picture below). The field of very high energy (VHE) gamma-ray astronomy is extremely young. The first source, the Crab Nebula, was detected in 1989. Since that time, nearly one hundred sources have been discovered. These different sources constitute a variety of astrophysical objects and phenomena. A particularly impressive source of high energy gamma-rays are Active Galactic Nuclei, or AGN. These sources emit large amounts of radiation due to a super massive black hole (greater than 100 million solar masses) at the center (“nuclei”) of the active galaxy. -
Lectures on Astronomy, Astrophysics, and Cosmology
Lectures on Astronomy, Astrophysics, and Cosmology Luis A. Anchordoqui Department of Physics and Astronomy, Lehman College, City University of New York, NY 10468, USA Department of Physics, Graduate Center, City University of New York, 365 Fifth Avenue, NY 10016, USA Department of Astrophysics, American Museum of Natural History, Central Park West 79 St., NY 10024, USA (Dated: Spring 2016) I. STARS AND GALAXIES minute = 1:8 107 km, and one light year × 1 ly = 9:46 1015 m 1013 km: (1) A look at the night sky provides a strong impression of × ≈ a changeless universe. We know that clouds drift across For specifying distances to the Sun and the Moon, we the Moon, the sky rotates around the polar star, and on usually use meters or kilometers, but we could specify longer times, the Moon itself grows and shrinks and the them in terms of light. The Earth-Moon distance is Moon and planets move against the background of stars. 384,000 km, which is 1.28 ls. The Earth-Sun distance Of course we know that these are merely local phenomena is 150; 000; 000 km; this is equal to 8.3 lm. Far out in the caused by motions within our solar system. Far beyond solar system, Pluto is about 6 109 km from the Sun, or 4 × the planets, the stars appear motionless. Herein we are 6 10− ly. The nearest star to us, Proxima Centauri, is going to see that this impression of changelessness is il- about× 4.2 ly away. Therefore, the nearest star is 10,000 lusory. -
Newsletter Archive the Skyscraper April 2011
50 Years of Manned Spaceflight• Yuri Gagarin • April 12, 1961 the vol. 38 no. 4 April Skyscraper 2011 Amateur Astronomical Society of Rhode Island 47 Peeptoad Road North Scituate, Rhode Island 02857 www.theSkyscrapers.org April Meeting with Steve Hubbard Seagrave Memorial Friday, April 1, 7:30pm Observatory is open at North Scituate Community Center to the public weather permitting The Mallincam Miracle: Saturdays: 8-10pm Real-Time Enhanced Observing of Deep Sky Objects and Planets Please note that the observatory may be inac- cessible for several weeks following a winter When I started observing over 35 years storm. See web site for updates. ago, visual observing was fun. Modest sized telescopes could show most deep sky objects visually from locations even near big cities. North Scituate Since then, light pollution has wiped out Community Center much of the night sky view for us. From All of our winter meetings (Dec-Mar) are held my backyard near Worcester, ever growing at the Community Center. From Seagrave light pollution has erased my ability to see Observatory, the Community Center is the first all but the brightest deep sky objects even building on the right side going south on Rt. with a 16 inch telescope. Since obtaining a 116 after the intersection of Rt. 6 Bypass (also Mallincam imaging system a year ago, my Rt. 101) and Rt. 116. Parking is across the street. interest in observing has been revitalized by amazing color images in real time literally cutting thru the light pollution and giving In this issue… views similar to those through telescopes 3 times the size that the Mallincam is attached 2 President’s Message to. -
Multi-Frequency Study on Markarian 421 During the First Two Years of Operation of the MAGIC Stereo Telescopes
Multi-frequency Study on Markarian 421 during the First Two Years of Operation of the MAGIC Stereo Telescopes Shang-yu Sun Munchen¨ 2014 Multi-frequency Study on Markarian 421 during the First Two Years of Operation of the MAGIC Stereo Telescopes Shang-yu Sun Dissertation an der Fakultat¨ fur¨ Physik der Ludwig–Maximilians–Universiat¨ Munchen¨ vorgelegt von Shang-yu Sun aus Kaohsiung, Taiwan München, den 22.09.2014 Erstgutachter: Prof. Dr. Christian Kiesling Zweitgutachter: Prof. Dr. Masahiro Teshima Tag der mündlichen Prüfung: 22.09.2014 Abstract Markarian 421 (Mrk 421) is one of the classical blazars at X-ray and very high energies (VHE; >100 GeV). Its spectral energy distribution (SED) can be accurately characterized by current instruments because of its close proximity, which makes Mrk 421 one of the best sources to study the nature of blazars. The goal of this PhD thesis is to better understand the mechanisms responsible for the broadband emission and the temporal evolution of Mrk 421. The results might be applied to other blazars which cannot be studied with this level of detail because their emissions are weaker, or they are located further away. This thesis reports results from ∼70 hours of observations with MAGIC in 2010 and 2011 (the first two years of the operation of the MAGIC stereo telescopes), as well as the results from the multi-wavelength (MW) observation campaigns in 2010 and 2011, where more than 20 instruments participated, covering energies from radio to VHE. The MW data from the 2010 and 2011 campaigns show that, for both years, the fractional variability Fvar increases with the energy for both the low-energy and the high-energy bumps in the SED of Mrk 421. -
Multiwavelength Periodicity Study of Markarian 501
A&A 501, 925–932 (2009) Astronomy DOI: 10.1051/0004-6361/200911814 & c ESO 2009 Astrophysics Multiwavelength periodicity study of Markarian 501 C. Rödig, T. Burkart, O. Elbracht, and F. Spanier Lehrstuhl für Astronomie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany e-mail: [email protected] Received 9 February 2009 / Accepted 27 April 2009 ABSTRACT Context. Active galactic nuclei (AGN) are highly variable emitters of electromagnetic waves from the radio to the gamma-ray regime. This variability may be periodic, which in turn could be the signature of a binary black hole. Systems of black holes are strong emitters of gravitational waves whose amplitude depends on the binary orbital parameters such as the component mass, the orbital semi-major-axis and eccentricity. Aims. It is our aim to prove the existence of periodicity of the AGN Markarian 501 from several observations in different wavelengths. A simultaneous periodicity in different wavelengths provides evidence of bound binary black holes in the core of AGN. Methods. Existing data sets from observations by Whipple, SWIFT, RXTE, and MAGIC have been analysed with the Lomb-Scargle method, the epoch-folding technique and the SigSpec software. Results. Our analysis shows a 72-day period, which could not be seen in previous works due to the limited length of observations. This does not contradict a 23-day period that can be derived as a higher harmonic from the 72-day period. Key words. galaxies: active – BL Lacertae objects: individual: Mrk 501 – X-rays: galaxies – gamma rays: observations 1. Introduction extremely weak, are also extremely pervasive and thus a novel and very promising way of exploring the universe. -
Multi-Wavelength Study of the Short Term Tev Flaring Activity From
Multi-wavelength study of the short term TeV flaring activity from the blazar Mrk 501 observed in June 2014 K K Singha,∗, H Bhatta, S Bhattacharyyaa,b, N Bhatta, A K Tickooa,b, R C Rannota,b aAstrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai - 400 085, India bHomi Bhabha National Institute, Mumbai - 400 094, India Abstract In this work, we study the short term flaring activity from the high synchrotron peaked blazar Mrk 501 detected by the FACT and H.E.S.S. telescopes in the en- ergy range 2-20 TeV during June 23-24, 2014 (MJD 56831.86-56831.94). We revisit this major TeV flare of the source in the context of near simultaneous multi-wavelength observations of γ–rays in MeV-GeV regime with Fermi-LAT, soft X-rays in 0.3-10 keV range with Swift-XRT, hard X-rays in 10-20 keV and 15-50 keV bands with MAXI and Swift-BAT respectively, UV-Optical with Swift- UVOT and 15 GHz radio with OVRO telescope. We have performed a detailed temporal and spectral analysis of the data from Fermi-LAT, Swift-XRT and Swift- UVOT during the period June 15-30, 2014 (MJD 56823-56838). Near simulta- neous archival data available from Swift-BAT, MAXI and OVRO telescope along with the V-band optical polarization measurements from SPOL observatory are also used in the study of giant TeV flare of Mrk 501 detected by the FACT and H.E.S.S. telescopes. No significant change in the multi-wavelength emission from radio to high energy γ–rays during the TeV flaring activity of Mrk 501 is observed except variation in soft X-rays. -
The VERITAS Extragalactic Science Program Is Well Established
2011 Fermi Symposium, Roma., May. 9-12 1 The VERITAS Extragalactic Science Program N. Galante Harvard-Smithsonian Center for Astrophysics for the VERITAS Collaboration http://veritas.sao.arizona.edu VERITAS is an array of four 12-m diameter imaging atmospheric-Cherenkov telescopes located in southern Arizona. Its aim is to study the very high energy (VHE: E > 100 GeV) γ-ray emission from astrophysical objects. The study of Active Galactic Nuclei (AGN) is intensively pursued through the VERITAS blazar key science project, but also through the large MWL observational campaigns on radio galaxies. The successful VERITAS AGN research program has provided insights to the jet inner structures and started a more detailed classification of blazars. Moreover, the synergy between Fermi and VERITAS on blazar observations resulted in important constraints on the extragalactic background light (EBL) through γ-ray observations, and on the cataloguing of the several AGN sub-classes . VERITAS discovered also the first extragalactic non-AGN γ-ray source. The discovery of gamma-ray emission from the starburst galaxy M 82 by VERITAS and Fermi provides important clues on possible mechanisms for accelerating cosmic rays. I. INTRODUCTION lations is of particular interest for the cosmic-ray com- munity. Beside AGN-related environments, starburst galax- The largest population of VHE-detected γ-ray ies are also good candidates as ultra-high energy cos- sources are blazars, a sub-category of AGNs in which mic rays accelerators. The active regions of starburst the ultra-relativistic jet, produced by the accretion of galaxies have a star formation rate about 10 times matter around a super-massive black hole, is aligned larger than the rate in normal galaxies of similar mass, within a few degrees to the observer’s line of sight [1]. -
X-Ray Flux and Spectral Variability of the Tev Blazars Mrk 421 and PKS 2155-304
galaxies Article X-ray Flux and Spectral Variability of the TeV Blazars Mrk 421 and PKS 2155-304 Alok C. Gupta Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital 263001, India; [email protected] Received: 20 July 2020; Accepted: 1 September 2020; Published: 4 September 2020 Abstract: We reviewed X-ray flux and spectral variability properties studied to date by various X-ray satellites for Mrk 421 and PKS 2155-304, which are TeV emitting blazars. Mrk 421 and PKS 2155-304 are the most X-ray luminous blazars in the northern and southern hemispheres, respectively. Blazars show flux and spectral variabilities in the complete electromagnetic spectrum on diverse timescales ranging from a few minutes to hours, days, weeks, months and even several years. The flux and spectral variability on different timescales can be used to constrain the size of the emitting region, estimate the super massive black hole mass, find the dominant emission mechanism in the close vicinity of the super massive black hole, search for quasi-periodic oscillations in time series data and several other physical parameters of blazars. Flux and spectral variability is also a dominant tool to explain jet as well as disk emission from blazars at different epochs of observations. Keywords: BL Lac objects; individual; Mrk 421; PKS 2155-304 galaxies; active galaxies; jets radiation mechanisms; non-thermal X-rays; galaxies 1. Introduction Blazar is a subclass of radio-loud (RL) active galactic nuclei (AGN) which includes BL Lacertae (BL Lacs) objects and flat spectrum radio quasars (FSRQs). Blazar’s central engine is a super massive 6 10 black hole (SMBH) of the mass range 10 M –10 M that accretes matter and produces relativistic jets pointing almost in the direction of observer’s line of sight [1]. -
Spectral Energy Distribution of Markarian 501: Quiescent State Versus Extreme Outburst
The Astrophysical Journal, 729:2 (9pp), 2011 March 1 doi:10.1088/0004-637X/729/1/2 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. SPECTRAL ENERGY DISTRIBUTION OF MARKARIAN 501: QUIESCENT STATE VERSUS EXTREME OUTBURST V. A. Acciari1, T. Arlen2,T.Aune3, M. Beilicke4, W. Benbow1,M.Bottcher¨ 5, D. Boltuch6, S. M. Bradbury7, J. H. Buckley4, V. Bugaev4, A. Cannon8, A. Cesarini9,L.Ciupik10, W. Cui11, R. Dickherber4,C.Duke12, M. Errando13, A. Falcone14,J.P.Finley11, G. Finnegan15, L. Fortson10, A. Furniss3, N. Galante1, D. Gall11,51, S. Godambe15, J. Grube10, R. Guenette16,G.Gyuk10, D. Hanna16, J. Holder6, D. Huang17,C.M.Hui15, T. B. Humensky18, A. Imran19, P. Kaaret20,N.Karlsson10, M. Kertzman21, D. Kieda15, A. Konopelko17, H. Krawczynski4,F.Krennrich19, A. S. Madhavan19,G.Maier16,52, S. McArthur4, A. McCann16, P. Moriarty22,R.A.Ong2,A.N.Otte3, D. Pandel20, J. S. Perkins1,A.Pichel23, M. Pohl19,52,53, J. Quinn8, K. Ragan16, L. C. Reyes24, P. T. Reynolds25, E. Roache1,H.J.Rose7, M. Schroedter19, G. H. Sembroski11, D. Steele10,54, S. P. Swordy18, M. Theiling1, S. Thibadeau4, A. Varlotta11, V. V. Vassiliev2,S.Vincent15, S. P. Wakely18,J.E.Ward8, T. C. Weekes1, A. Weinstein2, T. Weisgarber18, D. A. Williams3, M. Wood2, B. Zitzer11 (the VERITAS Collaboration), J. Aleksic´26, L. A. Antonelli27, P. Antoranz28, M. Backes29, J. A. Barrio30, D. Bastieri31, J. Becerra Gonzalez´ 32,33, W. Bednarek34, A. Berdyugin35, K. Berger32, E. Bernardini36, A. Biland37, O. Blanch26,R.K.Bock38, A. Boller37, G.