Massive Black Hole Binary Evolution David Merritt Rochester Institute of Technology
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1984 Statistics
NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary - 1984 Statistics February 1985 NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary - 1984 Statistics February 1985 Some Highlights of the 1984 Research Program • The 300-foot telescope was used to detect low-frequency carbon recombination lines from cold, diffuse Interstellar clouds in the direction of Cas A. Previously reported absorption lines were confirmed at 26 MHz and a number of other lines were identified in the 25 MHz to 68 MHz range. These lines promise to become an important diagnostic for the ionization conditions in cool interstellar clouds. • Extremely painstaking observations of several Abell clusters of galaxies with the 140-foot telescope have yielded three positive detections of the Sunyaev-Zeldovich effect. The dimunition in the brightness of the microwave background in the direction of clusters is the direct result of the Inverse Compton scattering of the 3° K blackbody photons by electrons in the Intracluster gas. The observations took full advantage of the low noise temperature, broadband, and excellent stability of the Green Bank 18-26 MHz maser system. • The J ■ 1*0 transition of the long-sought-after molecular ion, HCNff*", was detected with the 12-meter telescope at 74.1 GHz. The existence of protonated HCN is one of the prime tests of the theory of ion-molecule reaction schemes in interstellar chemistry. Virtually all CN-containing interstellar molecules, such as HCN, HNC, and many long-chain cyanopolyynes, form directly from HCNH+. • A high-resolution VLA survey of all catalogued, high surface brightness, compact objects in the southern galactic plane uncovered a few objects which are not classifiable into previously known SNR categories. -
The Title of My
Research in Astronomy and Astrophysics manuscript no. (LATEX: cgw.tex; printed on January 14, 2020; 2:35) Constraints on individual supermassive binary black holes using observations of PSR J1909 3744 − Yi Feng1,2,3, Di Li1,3, Yan-Rong Li4 and Jian-Min Wang4 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China ; [email protected] 2 University of Chinese Academy of Sciences, Beijing 100049, China 3 CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 4 Institute of High Energy Physics, Chinese Academy of Sciences,19B Yuquan Road, Beijing 100049, China Abstract We perform a search for gravitational waves (GWs) from several supermassive binary black hole (SMBBH) candidates (NGC 5548, Mrk 231, OJ 287, PG 1302-102, NGC 4151, Ark 120 and 3C 66B) in long-term timing observations of the pulsar PSR J1909 3744 − obtained using the Parkes radio telescope. No statistically significant signals were found. We constrain the chirp masses of those SMBBH candidates and find the chirp mass of NGC 5548 and3C66Btobeless than2.4 109 M and 2.5 109 M (with 95% confidence), respectively. × ⊙ × ⊙ Our upperlimits remaina factor of 3 to 370 abovethe likely chirp masses for these candidates as estimated from other approaches. The observations processed here provide upper limits on the GW strain amplitude that improve upon the results from the first Parkes Pulsar Timing arXiv:1907.03460v2 [astro-ph.IM] 13 Jan 2020 Array data release by a factor of 2 to 7. We investigate how information about the orbital pa- rameters can help improve the search sensitivity for individual SMBBH systems. -
Counting Gamma Rays in the Directions of Galaxy Clusters
A&A 567, A93 (2014) Astronomy DOI: 10.1051/0004-6361/201322454 & c ESO 2014 Astrophysics Counting gamma rays in the directions of galaxy clusters D. A. Prokhorov1 and E. M. Churazov1,2 1 Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany e-mail: [email protected] 2 Space Research Institute (IKI), Profsouznaya 84/32, 117997 Moscow, Russia Received 6 August 2013 / Accepted 19 May 2014 ABSTRACT Emission from active galactic nuclei (AGNs) and from neutral pion decay are the two most natural mechanisms that could establish a galaxy cluster as a source of gamma rays in the GeV regime. We revisit this problem by using 52.5 months of Fermi-LAT data above 10 GeV and stacking 55 clusters from the HIFLUCGS sample of the X-ray brightest clusters. The choice of >10 GeV photons is optimal from the point of view of angular resolution, while the sample selection optimizes the chances of detecting signatures of neutral pion decay, arising from hadronic interactions of relativistic protons with an intracluster medium, which scale with the X-ray flux. In the stacked data we detected a signal for the central 0.25 deg circle at the level of 4.3σ. Evidence for a spatial extent of the signal is marginal. A subsample of cool-core clusters has a higher count rate of 1.9 ± 0.3 per cluster compared to the subsample of non-cool core clusters at 1.3 ± 0.2. Several independent arguments suggest that the contribution of AGNs to the observed signal is substantial, if not dominant. -
198 8Apj. . .329. .532K the Astrophysical Journal, 329:532-550
.532K The Astrophysical Journal, 329:532-550,1988 June 15 © 1988. The American Astronomical Society. All rights reserved. Printed in U.S.A. .329. 8ApJ. 198 THE OPTICAL CONTINUA OF EXTRAGALACTIC RADIO JETS1 William C. Keel Sterrewacht Leiden Received 1987 August 11 ; accepted 1987 December 11 ABSTRACT Multicolor optical images have been used to measure the broad-band spectral shapes of radio jets known to show optical counterparts, and to search for such counterparts in additional objects. One new detection, the brightest knot in the NGC 6251 jet, is reported. In all cases, except part of the 3C 273 jet, the jet continua are well-represented by synchrotron spectra from truncated power-law electron distributions, with emitted-frame critical frequencies between 3 x 1014 and 2 x 1015 Hz. This may be due to fine structure in the jets or to the particle (re)acceleration process. Two hot spots (Pic A and 3C 303) differ from the jets, in showing unbroken power-law spectra from the radio to the B band. Image restoration has been used to examine the sub-arcsecond structure of the M87 jet and derive spectral shapes for various knots free of blending problems. The structure matches that seen in the radio to the Ol'S level, implying that the jet structure prevents particles from streaming freely over this distance (~30pc) Significant changes in turnover frequency occur from knot to knot, with an overall trend of higher frequency closer to the nucleus. Knot A is an exception, with a spectrum like the features near the core. An Appendix gives results of surface photometry for the program galaxies. -
University of Southampton Research Repository Eprints Soton
University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk UNIVERSITY OF SOUTHAMPTON The epoch and environmental dependence of radio-loud active galaxy feedback by Judith Ineson Thesis for the degree of Doctor of Philosophy in the FACULTY OF PHYSICAL SCIENCES AND ENGINEERING Department of Physics and Astronomy June 2016 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF PHYSICAL SCIENCES AND ENGINEERING Department of Physics and Astronomy Doctor of Philosophy THE EPOCH AND ENVIRONMENTAL DEPENDENCE OF RADIO-LOUD ACTIVE GALAXY FEEDBACK by Judith Ineson This thesis contains the first systematic X-ray investigation of the relationships between the properties of different types of radio-loud AGN and their large-scale environments, using samples at two distinct redshifts to isolate the effects of evolution. I used X-ray ob- servations of the galaxy clusters hosting the radio galaxies to characterise the properties of the environments and compared them with the low-frequency radio properties of the AGN. -
Tev Gamma-Ray Observations of Mrk421 and H1426+428 with TACTIC Imaging Telescope
TeV Gamma-Ray Observations of Mrk421 and H1426+428 with TACTIC Imaging Telescope A Thesis submitted to the University of Mumbai for the Ph. D. (SCIENCE) Degree in PHYSICS Submitted By Kuldeep Kumar Yadav Under the Guidance of Dr. R. C. Rannot arXiv:1109.1967v1 [astro-ph.CO] 9 Sep 2011 Astrophysical Sciences Division Bhabha Atomic Research Centre Trombay, Mumbai 400 085 October 2010 Dedicated to My Parents ii iii STATEMENT BY THE CANDIDATE As required by the University Ordinance 770, I wish to state that the work embodied in this thesis titled “ TeV Gamma-Ray Observations of Mrk421 and H1426+428 with TACTIC Imaging Telescope” forms my own contri- bution to the research work carried out under the guidance of Dr. R.C. Ran- not at Astrophysical Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai. This work has not been submitted for any other degree of this or any other University. Whenever reference have been made to previ- ous works of others, it has been clearly indicated as such and included in the Bibliography. ———————————– Signature of candidate Name : Kuldeep Kumar Yadav Certified by ———————————– Signature of Guide Name : Dr. R. C. Rannot Abstract We have observed extragalactic sources Mrk421 (z=0:30) and H1426+428 (z=0:129) in very high energy γ-ray region using TACTIC telescope at Mount Abu (24:6◦N, 72:7◦E, 1300 m asl), Rajasthan, India. Both of these sources belong to the blazar sub-class of active galactic nuclei whose jets are closely aligned to our line of sight. Blazars are most extreme and pow- erful variable sources of radiation of energies ranging from the radio to the γ-ray regimes. -
The Jets in Radio Galaxies
The jets in radio galaxies Martin John Hardcastle Churchill College September 1996 A dissertation submitted in candidature for the degree of Doctor of Philosophy in the University of Cambridge i `Glaucon: ª...But how did you mean the study of astronomy to be reformed, so as to serve our pur- poses?º Socrates: ªIn this way. These intricate traceries on the sky are, no doubt, the loveliest and most perfect of material things, but still part of the visibleworld, and therefore they fall far short of the true realities Ð the real relativevelocities,in theworld of purenumber and all geometrical ®gures, of the movements which carry round the bodies involved in them. These, you will agree, can be conceived by reason and thought, not by the eye.º Glaucon: ªExactly.º Socrates: ªAccordingly, we must use the embroidered heaven as a model to illustrateour study of these realities, just as one might use diagrams exquisitely drawn by some consummate artist like Daedalus. An expert in geometry, meeting with such designs, would admire their ®nished workmanship, but he wouldthink it absurd to studythem in all earnest with the expectation of ®nding in their proportionsthe exact ratio of any one number to another...º ' Ð Plato (429±347 BC), The Republic, trans. F.M. Cornford. ii Contents 1 Introduction 1 1.1 Thisthesis...................................... ... 1 1.2 Abriefhistory................................... .... 2 1.3 Synchrotronphysics........ ........... ........... ...... 4 1.4 Currentobservationalknowledgeintheradio . ............. 5 1.4.1 Jets ........................................ 6 1.4.2 Coresornuclei ................................. 6 1.4.3 Hotspots ..................................... 7 1.4.4 Largescalestructure . .... 7 1.4.5 Theradiosourcemenagerie . .... 8 1.4.6 Observationaltrends . -
Extragalactic Radio Jets
Annual Reviews www.annualreviews.org/aronline Ann. Rev. Astron.Astrophys. 1984. 22 : 319-58 Copyright© 1984 by AnnualReviews Inc. All rights reserved EXTRAGALACTIC RADIO JETS Alan H. Bridle National Radio AstronomyObservatory, 1 Charlottesville, Virginia 22901 Richard A. Perley National Radio Astronomy Observatory, Socorro, New Mexico 87801 1. INTRODUCTION Powerful extended extragalactic radio sources pose two vexing astro- physical problems [reviewed in (147) and (157)]. First, from what energy reservoir do they draw their large radio luminosities (as muchas 10a8 W between 10 MHzand 100 GHz)?Second, how does the active center in the parent galaxy or QSOsupply as muchas 10~4 J in relativistic particles and fields to radio "lobes" up to several hundredkiloparsecs outside the optical object? Newaperture synthesis arrays (68, 250) and new image-processing algorithms (66, 101, 202, 231) have recently allowed radio imaging subarcsecond resolution with high sensitivity and high dynamicrange; as a result, the complexityof the brighter sources has been revealed clearly for the first time. Manycontain radio jets, i.e. narrow radio features between compact central "cores" and more extended "lobe" emission. This review examinesthe systematic properties of such jets and the dues they give to the by PURDUE UNIVERSITY LIBRARY on 01/16/07. For personal use only. physics of energy transfer in extragalactic sources. Wedo not directly consider the jet production mechanism,which is intimately related to the Annu. Rev. Astro. Astrophys. 1984.22:319-358. Downloaded from arjournals.annualreviews.org first problemnoted above--for reviews, see (207) and (251). 1. i Why "’Jets"? Baade & Minkowski(3) first used the term jet in an extragalactic context, describing the train of optical knots extending ,-~ 20" from the nucleus of M87; the knots resemble a fluid jet breaking into droplets. -
Structure in Radio Galaxies
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Bibliography, Christopher P. O'dea Refereed Articles 1. CP O'dea, WA
Bibliography, Christopher P. O'Dea Refereed Articles 1. C. P. O'Dea, W. A. Dent & T. J. Balonek, \Opacity Effects at Radio Wavelengths in the Quasar 1308 + 326," Astrophysical Journal (Letters), 266, L1{L3 (1983). 2. C. P. O'Dea, W. A. Dent, T. J. Balonek & J. E. Kapitzky, \2.7 GHz Observations of Four Radio Polarization Rotators," Astronomical Journal, 88, 1616{1625 (1983). 3. W. A. Dent, C. P. O'Dea, T. J. Balonek, R. W. Hobbs & R. J. Howard, \A Rapid Millimeter Wave Outburst in the Nucleus of NGC 1275," Nature, 306, 41{42 (1983). 4. B. J. Wills et al., \The QSO 1156 + 295: A Study of Recent Activity from Radio to Ultraviolet Wavelengths," Astrophysical Journal, 274, 62{85 (1983) 5. A. E. Glassgold et al., \Multifrequency Observations of the Flaring Quasar 1156 + 295," Astrophysical Journal, 274, 101{112 (1983). 6. J. N. Bregman et al., \Multifrequency Observations of the BL Lac Object 0735 + 178," Astrophysical Journal, 276, 454{465 (1984). 7. C. P. O'Dea, W. A. Dent & T. J. Balonek, \The 20 Year Spectral Evolution of the Radio Nucleus of NGC 1275," Astrophysical Journal, 278, 89{95 (1984). 8. J. A. Eilek, J. O. Burns, C. P. O'Dea & F. N. Owen, \What Bends 3C 465?" Astrophysical Journal, 278, 37{50 (1984). 9. C. P. O'Dea & F. N. Owen, \VLA Observations of 57 Sources in Clusters of Galaxies," Astronomical Journal, 90, 927{953 (1985). 10. C. P. O'Dea & F. N. Owen, \The Global Properties of a Representa- tive Sample of 51 Narrow Angle Tail Radio Sources in the Directions of Abell Clusters," Astronomical Journal, 90, 954{972 (1985). -
Cycle 12 Abstract Catalog
Cycle 12 Abstract Catalog Generated April 04, 2003 ================================================================================ Proposal Category: GO Scientific Category: ISM AND CIRCUMSTELLAR MATTER ID: 9718 Title: SMC Extinction Curve Towards a Quiescent Molecular Cloud PI: Francois Boulanger PI Institution: Institut d'Astrophysique Spatiale The lack of 2175 A bump in the SMC extinction curve is interpreted as an absence of small carbon grains. ISO Mid-IR observations support this interpretation by showing that PAH features are absent in the spectra of SMC and LMC massive star forming regions. However, the only ISO observation of an SMC quiescent molecular cloud shows all PAH features, indicating a PAH abundance relative to large dust grains similar to that of Milky Way clouds. We identified a reddened B2III star associated with this cloud. We propose to observe it with STIS. This observation will provide the first measure of the extinction properties of SMC dust away from star forming regions. It will allow us to disentangle the effects of metallicity and massive stars on the SMC extinction curve and dust composition and to assess the relevance of the SMC bump-free extinction curve to low metallicity and/or starburst galaxies in general. ================================================================================ Proposal Category: GO Scientific Category: STELLAR POPULATIONS ID: 9719 Title: Search For Metallicity Spreads in M31 Globular Clusters PI: Terry Bridges PI Institution: Anglo-Australian Observatory Our recent deep HST photometry of the M31 halo globular cluster (GC) Mayall~II, also called G1, has revealed a red-giant branch with a clear spread that we attribute to an intrinsic metallicity dispersion of at least 0.4 dex in [Fe/H]. -
WISE J233237.05–505643.5: a Double-Peaked, Broad-Lined Active Galactic Nucleus with a Spiral-Shaped Radio Morphology
WISE J233237.05–505643.5: A Double-peaked, Broad-lined Active Galactic Nucleus with a Spiral-shaped Radio Morphology. The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Tsai, Chao-Wei, T. H. Jarrett, Daniel Stern, Bjorn Emonts, R. Scott Barrows, Roberto J. Assef, Ray P. Norris, et al. 2013. “WISE J233237.05–505643.5: A Double-peaked, Broad-lined Active Galactic Nucleus with a Spiral-shaped Radio Morphology.” The Astrophysical Journal 779 (1) (December 10): 41. doi:10.1088/0004-637x/779/1/41. http://dx.doi.org/10.1088/0004-637X/779/1/41. Published Version 10.1088/0004-637X/779/1/41;doi:10.1088/0004-637x/779/1/41 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:11829463 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA The Astrophysical Journal, 779:41 (14pp), 2013 December 10 doi:10.1088/0004-637X/779/1/41 C 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. WISE J233237.05−505643.5: A DOUBLE-PEAKED, BROAD-LINED ACTIVE GALACTIC NUCLEUS WITH A SPIRAL-SHAPED RADIO MORPHOLOGY Chao-Wei Tsai1,2, T. H. Jarrett3, Daniel Stern2, Bjorn Emonts4,5, R. Scott Barrows6, Roberto J. Assef2,7, Ray P. Norris5, Peter R. M. Eisenhardt2, Carol Lonsdale8, Andrew W.