Active Galaxies NewsletterAn electronic publication dedicated to the observations and theory of active galaxies
Edited by Megan Argo
The Active Galaxies Newsletter is an electronic publication dedicated to the observation and theory of active galaxies. It is intended to be used to notify others in the field of recently accepted papers, conference proceedings and dissertations, and also contains announcements of jobs and conferences. It is produced monthly and sent to over 600 subscribers.
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|Active||An electronic publication dedicated to|
|Galaxies||the observation and theory of|
|No. 223 -- May 2016||Editor: Megan Argo (firstname.lastname@example.org)|
Jobs Adverts - Meetings Adverts - Special Announcements
Welcome to all the new subscribers, and thanks to everyone who contributed to this issue of the Active Galaxies Newsletter.
This newsletter is intended to disseminate paper abstracts, meeting announcements, job adverts and other information which may be of interest to the active galaxies community. It is produced monthly and, whilst the deadline for contributions is the last day of the month, contributions may be submitted at any time.
The Latex macros for submitting abstracts and dissertation abstracts are appended to each issue of the newsletter and are also available on the web page. Please note that the editor may reject submissions which do not use the template. As always, any suggestions or feedback regarding the newsletter are welcome.
Thanks for your continued subscription.
Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy NGC 1365
Davide Lena1,2,3, Andrew Robinson1, Thaisa Storchi-Bergmann4, Guilherme S. Couto4, Allan Schnorr-Müller5,6 & Rogemar A. Riffel7
1. School of Physics & Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623-5603, USA
2. SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, NL-3584 CA Utrecht, The Netherlands
3. Department of Astrophysics/IMAPP, Radboud University, Nijmegen, PO Box 9010, NL-6500 GL Nijmegen, The Netherlands
4. Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, Brazil
5. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, D-85741, Garching, Germany
6. CAPES Foundation, Ministry of Education of Brazil, 70040-020, Brasilia, Brazil
7. Universidade Federal de Santa Maria, Departamento de Física, 97105-900, Santa Maria, RS, Brazil
We observed the nuclear region of the galaxy NGC 1365 with the integral field unit of the Gemini Multi Object Spectrograph mounted on the GEMINI-South telescope. The field of view covers 13"×6" (1173×541 pc2) centered on the nucleus, at a spatial resolution of 52 pc. The spectral coverage extends from 5600Å to 7000Å, at a spectral resolution R=1918. NGC 1365 hosts a Seyfert 1.8 nucleus, and exhibits a prominent bar extending out to 100" (9 kpc) from the nucleus. The field of view lies within the inner Lindblad resonance. Within this region, we found that the kinematics of the ionized gas (as traced by [OI], [NII], Hα, and [SII]) is consistent with rotation in the large-scale plane of the galaxy. While rotation dominates the kinematics, there is also evidence for a fan-shaped outflow, as found in other studies based on the [OIII] emission lines. Although evidence for gas inflowing along nuclear spirals has been found in a few barred galaxies, we find no obvious signs of such features in the inner kiloparsec of NGC 1365. However, the emission lines exhibit a puzzling asymmetry that could originate from gas which is slower than the gas responsible for the bulk of the narrow-line emission. We speculate that it could be tracing gas which lost angular momentum, and is slowly migrating from the inner Lindblad resonance towards the nucleus of the galaxy.
Accepted by MNRAS. DOI: 10.1093/mnras/stw896
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1604.03994
NuSTAR reveals the extreme properties of the super-Eddington accreting super massive black hole in PG 1247+267
G. Lanzuisi1,2, M. Perna1,2, A. Comastri2, M. Cappi3, M. Dadina3, A. Marinucci4, A. Masini1,2, G. Matt4, F. Vagnetti5, C. Vignali1,2, D. R. Ballantyne6, F. E. Bauer7,8,9, S. E. Boggs10, W. N. Brandt11,12,13, M. Brusa1,2, F. E. Christensen14, W. W. Craig10,15, A. C. Fabian16, D. Farrah17, C. J. Hailey18, F. A. Harrison19, B. Luo20,21, E. Piconcelli22, S. Puccetti23,22, C. Ricci7, C. Saez24, D. Stern25, D. J. Walton19,25 and W. W. Zhang26
1. Dipartimento di Fisica e Astronomia, Università di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna, Italy
2. INAF - Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna, Italy
3. INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica, Via Piero Gobetti 101, I-40129 Bologna, Italy
4. Dipartimento di Matematica e Fisica, Università di Roma Tre, Via della Vasca Navale 84, I-00146 Roma, Italy
5. Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma, Italy
6. Center for Relativistic Astrophysics, Georgia Institute of Technology, 837 State St., Atlanta, GA 30332, USA
7. Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
8. Millennium Institute of Astrophysics, Vicuna Mackenna 4860, 7820436 Macul, Santiago, Chile
9. Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
10. Space Science Laboratory, University of California, Berkeley, CA 94720, USA
11. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
12. Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
13. Department of Physics, 104 Davey Lab, The Pennsylvania State University, University Park, PA 16802, USA
14. DTU Space National Space Institute, Technical University of Denmark, Elektrovej 327, 2800 Lyngby, Denmark
15. Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
16. Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
17. Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA
18. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
19. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
20. School of Astronomy and Space Science, Nanjing University, Nanjing, 210093, China
21. Key laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, China
22. INAF - Osservatorio Astronomico di Roma, Via di Frascati, 33, I-00040 Monteporzio Catone (Roma), Italy
23. ASDC-ASI, Via del Politecnico, 00133 Roma, Italy
24. Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 305348, Korea
25. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
26. NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
PG1247+267 is one of the most luminous known quasars at z∼2, and a strongly super-Eddington accreting SMBH candidate. We obtained NuSTAR data of this source in December 2014 with the aim of studying the high-energy emission of this intriguing source, leveraging the broad band covered by the new NuSTAR and the archival XMM-Newton data. Several measurements are in agreement with the super-Eddington scenario for PG1247+267: the soft power-law (Γ=2.3±0.1); the weak ionized Fe emission line and a hint of the presence of outflowing ionized gas surrounding the SMBH. The presence of an extreme reflection component is instead at odds with the high accretion rate proposed for this quasar. This can be explained with three different scenarios, all of them in good agreement with the existing data, but implying very different conclusions: i) a variable primary power-law observed in a low state, superimposed on a reflection component echoing a past, higher flux state; ii) a power-law continuum obscured by an ionized, Compton thick, partial covering absorber; iii) a relativistic disk reflector in a lamp post geometry, with low coronal height and high BH spin. The first model is able to explain the high reflection component in terms of variability. The second does not require any reflection to reproduce the hard emission, while a rather low high-energy cut-off of ∼100 keV is detected, for the first time in such a high redshift source. The third model require a face-on geometry, which may affect the SMBH mass and Eddington ratio measurements. Deeper X-ray broad band data are required in order to disentangle between these possibilities.
Accepted by A&A on Mar 21 2016
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1604.02462
Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event
M. Kadler1, F. Krauß1,2, K. Mannheim1, R. Ojha3,4,5, C. Müller1,6, R. Schulz1,2, G. Anton7, W. Baumgartner3, T. Beuchert1,2, S. Buson8,9, B. Carpenter5, T. Eberl7, P.G. Edwards10, D. Eisenacher Glawion1, D. Elsässer1, N. Gehrels3, C. Gräfe1,2, H. Hase11, S. Horiuchi12, C.W. James7, A. Kappes1, A. Kappes7, U. Katz7, A. Kreikenbohm1,2, M. Kreter1,7, I. Kreykenbohm2, M. Langejahn1,2, K. Leiter1,2, E. Litzinger1,2, F. Longo13,14, J.E.J. Lovell15, J. McEnery3, C. Phillips10, C. Plötz11, J. Quick16, E. Ros17,18,19, F.W. Stecker3,20, T. Steinbring1,2, J. Stevens10, D.J. Thompson3, J. Trüstedt1,2, A.K. Tzioumis10, J. Wilms2, J.A. Zensus17
1. Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Emil-Fischer-Str. 31, 97074 Würzburg, Germany
2. Dr. Remeis Sternwarte & ECAP, Universität Erlangen-Nürnberg, Sternwartstrasse 7, 96049 Bamberg, Germany
3. NASA, Goddard Space Flight Center, Greenbelt MD 20771, USA
4. University of Maryland, Baltimore County, Baltimore MD 21250, USA
5. Catholic University of America, Washington DC 20064, USA
6. Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010, 6500 GL, Nijmegen, The Netherlands
7. ECAP, Universität Erlangen-Nürnberg, Erwin-Rommel-Str. 1, 91058 Erlangen, Germany
8. Istituto Nazionale di Fisica Nucleare, Sezione di Padova, 35131 Padova, Italy
9. Dipartimento di Fisica e Astronomia "G. Galilei", Universita di Padova, 35131 Padova, Italy
10. CSIRO Astronomy and Space Science, ATNF, PO Box 76, Epping NSW 1710, Australia
11. Bundesamt für Kartographie und Geodäsie, 93444 Bad Kötzting, Germany
12. CSIRO Astronomy and Space Science, Canberra Deep Space Communications Complex, PO Box 1035, Tuggeranong ACT 2901, Australia
13. Dip. di Fisica, Universita' di Trieste, 34128 Trieste, Italy
14. INFN, 34131 Trieste, Italy
15. School of Mathematics & Physics, University of Tasmania, Private Bag 37, Hobart, 7001 Tasmania, Australia
16. Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, South Africa
17. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
18. Observatori Astronòmic, Universitat de València, C/ Catedrático José Beltrán no. 2, 46980 Paterna, València, Spain
19. Departament d'Astronomia i Astrofísica, Universitat de València, C/ Dr. Moliner 50, 46100 Burjassot, València, Spain
20. Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA 90095
The astrophysical sources of the extraterrestrial, very-high energy neutrinos detected by the IceCube collaboration remain to be identified. Gamma-ray (γ-ray) blazars have been predicted to yield a cumulative neutrino signal exceeding the atmospheric background above energies of 100 TeV, assuming that both the neutrinos and the γ-ray photons are produced by accelerated protons in relativistic jets. As the background spectrum falls steeply with increasing energy, the individual events with the clearest signature of being of extraterrestrial origin are those at PeV energies. Inside the large positional-uncertainty fields of the first two PeV neutrinos detected by IceCube, the integrated emission of the blazar population has a sufficiently high electromagnetic flux to explain the detected IceCube events, but fluences of individual objects are too low to make an unambiguous source association. Here, we report that a major outburst of the blazar PKS B1424-418 occurred in temporal and positional coincidence with a third PeV-energy neutrino event (HESE-35) detected by IceCube. Based on an analysis of the full sample of γ-ray blazars in the HESE-35 field, we show that the long-term average γ-ray emission of blazars as a class is in agreement with both the measured all-sky flux of PeV neutrinos and the spectral slope of the IceCube signal. The outburst of PKS B1424-418 provides an energy output high enough to explain the observed PeV event, suggestive of a direct physical association.
Nature Physics (2016). DOI: 10.1038/nphys3715
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1602.02012
Long-term X-Ray Spectral Variability in AGN from the Palomar sample observed by Swift
S. D. Connolly1, I. M. McHardy1, C. J. Skipper1,2, D. Emmanoulopoulos1
1. Physics & Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
2. Jodrell Bank Centre for Astrophysics, Alan Turing Building, The University of Manchester, Manchester, M13 9PL, UK
We present X-ray spectral variability of 24 local active galactic nuclei (AGN) from the Palomar sample of nearby galaxies, as observed mainly by Swift. From hardness ratio measurements, we find that 18 AGN with low accretion rates show hardening with increasing count rate, converse to the softer-when-brighter behaviour normally observed in AGN with higher accretion rates. Two AGN show softening with increasing count rate, two show more complex behaviour, and two do not show any simple relationship. Sufficient data were available for the spectra of 13 AGN to be summed in flux-bins. In 9 of these sources, correlated luminosity-dependent changes in the photon index (Γ) of a power-law component are found to be the main cause of hardness variability. For 6 objects, with a low accretion rate as a fraction of the Eddington rate (ṁEdd), Γ is anticorrelated with ṁEdd, i.e. 'harder-when-brighter' behaviour is observed. The 3 higher-ṁEdd-rate objects show a positive correlation between Γ and ṁEdd. This transition from harder-when-brighter at low ṁEdd to softer-when-brighter at high ṁEdd can be explained by a change in the dominant source of seed-photons for X-ray emission from cyclo-synchrotron emission from the Comptonising corona itself to thermal seed-photons from the accretion disc. This transition is also seen in the 'hard state' of black hole X-ray binaries (BHXRBs). The results support the idea that LINERs are analogues of BHXRBs in the hard state and that Seyferts are analogues of BHXRBs in either the high-accretion-rate end of the hard state or in the hard-intermediate state.
Accepted by MNRAS. DOI: 10.1093/mnras/stw878
E-mail contact: firstname.lastname@example.org
Preprint available at http://mnras.oxfordjournals.org/content/early/2016/04/15/mnras.stw878.abstract
The Role of Radiation Pressure in the Narrow Line Regions of Seyfert Host Galaxies
Rebecca L. Davies1, Michael A. Dopita1,2, Lisa Kewley1,3, Brent Groves1, Ralph Sutherland1, Elise J. Hampton1, Prajval Shastri4, Preeti Kharb4, Harish Bhatt4, Julia Scharwächter5, Chichuan Jin6, Julie Banfield1,7, Ingyin Zaw8, Bethan James9, Stéphanie Juneau10, & Shweta Srivastava11
1. Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia
2. Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia
3. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, U.S.A.
4. Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034, India
5. LERMA, Observatoire de Paris, PSL, CNRS, Sorbonne Universités, UPMC, F-75014 Paris, France
6. Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
7. ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO)
8. New York University (Abu Dhabi) , 70 Washington Sq. S, New York, NY 10012, USA
9. Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA, UK
10. CEA-Saclay, DSM/IRFU/SAp, 91191 Gif-sur-Yvette, France
11. Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India
We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-AGN mixing curves on standard emission line diagnostic diagrams which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ∼ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ∼ 0 to -3.4 < log U < -3.2. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kpc scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.
Accepted for publication in ApJ
E-mail contact: Rebecca.Davies@anu.edu.au
Preprint is available at http://arxiv.org/abs/1604.06104
Active galactic nuclei at z∼1.5: II. Black Hole Mass estimation by means of broad emission lines
J. E. Mejia-Restrepo1, B. Trakhtenbrot2, P. Lira1, H. Netzer3, D. M. Capellupo3,4
1. Departamento de Astronomía, Universidad de Chile, Camino el Observatorio 1515, Santiago, Chile
2. Institute for Astronomy, Dept. of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland
3. School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
4. Department of Physics, McGill University, Montreal, Quebec, H3A 2T8, Canada
This is the second in a series of papers aiming to test how the mass (MBH), accretion rate (Ṁ) and spin (a☆) of super massive black holes (SMBHs) determine the observed properties of type-I active galactic nuclei (AGN). Our project utilizes a sample of 39 unobscured AGN at z≃1.55 observed by VLT/X-shooter, selected to map a large range in MBH and L/LEdd and covers the most prominent UV-optical (broad) emission lines, including Hα, Hβ, MgII, and CIV. This paper focuses on single-epoch, "virial" MBH determinations from broad emission lines and examine the implications of different continuum modeling approaches in line width measurements. We find that using a local power-law continuum instead of a physically-motivated thin disk continuum leads to only slight underestimation of the FWHM of the lines and the associated MBH(FWHM). However, the line dispersion σ and associated MBH(σ) are strongly affected by the continuum placement and provides less reliable mass estimates than FWHM-based methods. Our analysis shows that Hα, Hβ and MgII can be safely used for virial MBH estimation. The CIV line, on the other hand, is not reliable in the majority of the cases, this may indicate that the gas emitting this line is not virialized. While Hα and Hβ show very similar line widths, the mean FWHM(MgII) is about 30% narrower than FWHM(Hβ). We confirm several recent suggestions to improve the accuracy in CIV-based mass estimates, relying on other UV emission lines. Such improvements do not reduce the scatter between CIV-based and Balmer-line-based mass estimates.
Accepted by MNRAS. DOI: 10.1093/mnras/stw568
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1603.03437
CIV Broad Absorption Line Acceleration in Sloan Digital Sky Survey Quasars
C. J. Grier1,2, W. N. Brandt1,2,3, P. B. Hall4, J. R. Trump1,2,5, N. Filiz Ak6, S. F. Anderson7, Paul J. Green8, D. P. Schneider1,2, M. Sun1,9, M. Vivek10, T. G. Beatty1,11, Joel R. Brownstein10, and Alexandre Roman-Lopes12
1. Department of Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802, USA
2. Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
3. Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
4. Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3, Canada
5. Hubble Fellow
6. Faculty of Sciences, Department of Astronomy and Space Sciences, Erciyes University, 38039 Kayseri, Turkey
7. Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
8. Harvard Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USA
9. Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005, China
10. Department of Physics and Astronomy, University of Utah, 115 S. 1400 E., Salt Lake City, UT 84112, USA
11. Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802, USA
12. Departamento de Fisica, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena, Chile
We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over timescales of ≈2.5-5.5 years in the quasar rest frame. We carefully select acceleration candidates by requiring monolithic velocity shifts over the entire BAL trough, avoiding BALs with velocity shifts that might be caused by profile variability. The CIV BALs of two quasars show velocity shifts consistent with the expected signatures of BAL acceleration, and the BAL of one quasar shows a velocity-shift signature of deceleration. In our two acceleration candidates, we see evidence that the magnitude of the acceleration is not constant over time; the magnitudes of the change in acceleration for both acceleration candidates are difficult to produce with a standard disk-wind model or via geometric projection effects. We measure upper limits to acceleration and deceleration for 76 additional BAL troughs and find that the majority of BALs are stable to within about 3% of their mean velocities. The lack of widespread acceleration/deceleration could indicate that the gas producing most BALs is located at large radii from the central black hole and/or is not currently strongly interacting with ambient material within the host galaxy along our line of sight.
Accepted for publication in the Astrophysical Journal.
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1604.07410
Active galactic nuclei at z∼1.5: III. Accretion discs and black hole spin
D. M. Capellupo1,2, H. Netzer1, P. Lira3, B. Trakhtenbrot4, J. Mejía-Restrepo3
1. School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
2. Department of Physics, McGill University, Montreal, Quebec, H3A 2T8, Canada
3. Departamento de Astronomía, Universidad de Chile, Camino del Observatorio 1515, Santiago, Chile
4. Institute for Astronomy, Dept. of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland
This is the third paper in a series describing the spectroscopic properties of a sample of 39 AGN at z∼1.5, selected to cover a large range in black hole mass (MBH) and Eddington ratio (L/LEdd). In this paper, we continue the analysis of the VLT/X-shooter observations of our sample with the addition of 9 new sources. We use an improved Bayesian procedure, which takes into account intrinsic reddening, and improved MBH estimates, to fit thin accretion disc (AD) models to the observed spectra and constrain the spin parameter (a☆) of the central black holes. We can fit 37 out of 39 AGN with the thin AD model, and for those with satisfactory fits, we obtain constraints on the spin parameter of the BHs, with the constraints becoming generally less well defined with decreasing BH mass. Our spin parameter estimates range from ∼-0.6 to maximum spin for our sample, and our results are consistent with the "spin-up" scenario of BH spin evolution. We also discuss how the results of our analysis vary with the inclusion of non-simultaneous GALEX photometry in our thin AD fitting. Simultaneous spectra covering the rest-frame optical through far-UV are necessary to definitively test the thin AD theory and obtain the best constraints on the spin parameter.
Accepted by MNRAS. DOI: 10.1093/mnras/stw937
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1604.05310
Evidence for two Lognormal States in Multi-wavelength Flux Variation of FSRQ PKS 1510-089
Pankaj Kushwaha1, Sunil Chandra2, Ranjeev Misra1, S. Sahayanathan3, K. P. Singh2, K. S. Baliyan4
1. Inter-University Center for Astronomy and Astrophysics, Pune 411007, India
2. Department of Astronomy & Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005, India
3. Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085, India
4. Physical Research Laboratory, Ahmedabad 380009, India
We present a systematic characterization of multi-wavelength emission from blazar PKS 1510-089 using well-sampled data at infrared(IR)-optical, X-ray and γ-ray energies. The resulting flux distributions, except at X-rays, show two distinct lognormal profiles corresponding to a high and a low flux level. The dispersions exhibit energy dependent behavior except for the LAT γ-ray and optical B-band. During the low level flux states, it is higher towards the peak of the spectral energy distribution, with γ-ray being intrinsically more variable followed by IR and then optical, consistent with mainly being a result of varying bulk Lorentz factor. On the other hand, the dispersions during the high state are similar in all bands except optical B-band, where thermal emission still dominates. The centers of distributions are a factor of ∼4 apart, consistent with anticipation from studies of extragalactic γ-ray background with the high state showing a relatively harder mean spectral index compared to the low state.
Published in ApJL, 822, L13 (2016); DOI: 10.3847/2041-8205/822/1/L13
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1604.04335
MUSE 3D Spectroscopy and Kinematics of the gigahertz peaked spectrum Radio Galaxy PKS 1934-63: Interaction, Recently Triggered AGN and Star Formation
Nathan Roche1, Andrew Humphrey1, Patricio Lagos1, Polychronis Papaderos1, Marckelson Silva1,2, Leandro S. M. Cardoso1,2, Jean Michel Gomes1
1. Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
2. Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
We observe the radio galaxy PKS 1934-63 (at z=0.1825) using MUSE (Multi Unit Spectroscopic Explorer) on the Very Large Telescope (VLT). The radio source is GigaHertz Peaked Spectrum and compact (0.13 kpc), implying an early stage of evolution (≤ 104 yr). Our data show an interacting pair of galaxies, projected separation 9.1 kpc, velocity difference Δ(v)=216 km s-1. The larger galaxy is a M☆≃1011M⊙ spheroidal with the emission-line spectrum of a high-excitation young radio acive galactic nucleus (AGN, e.g. strong [OI]6300 and [OIII]5007). Emission-line ratios indicate a large contribution to the line luminosity from high-velocity shocks (≃550 km s-1) . The companion is a non-AGN disk galaxy, with extended Hα emission from which its star-formation rate is estimated as 0.61 M⊙ yr-1. Both galaxies show rotational velocity gradients in Hα and other lines, with the interaction being prograde-prograde. The SE-NW velocity gradient of the AGN host is misaligned from the E-W radio axis, but aligned with a previously discovered central ultraviolet source, and a factor 2 greater in amplitude in Hα than in other (forbidden) lines (e.g. [OIII]5007). This could be produced by a fast rotating (100-150 km s-1) disk with circumnuclear star-formation. We also identify a broad component of [OIII]5007 emission, blueshifted with a velocity gradient aligned with the radio jets, and associated with outflow. However, the broad component of [OI]6300 is redshifted. In spectral fits, both galaxies have old stellar populations plus ∼ 0.1% of very young stars, consistent with the galaxies undergoing first perigalacticon, triggering infall and star-formation from ∼40 Myr ago followed by the radio outburst.
Accepted by MNRAS. DOI: 10.1093/mnras/stw765
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1604.00309
Using leaked power to measure intrinsic AGN power spectra of red-noise time series
S. F. Zhu1, Y. Q. Xue1
1. CAS Key Laboratory for Researches in Galaxies and Cosmology, Center for Astrophysics, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026, China
Fluxes emitted at different wavebands from active galactic nuclei (AGNs) fluctuate at both long and short timescales. The variation can typically be characterized by a broadband power spectrum, which exhibits a red-noise process at high frequencies. The standard method of estimating power spectral density (PSD) of AGN variability is easily affected by systematic biases such as red-noise leakage and aliasing, in particular, when the observation spans a relatively short period and is gapped. Focusing on the high-frequency PSD that is strongly distorted due to red-noise leakage and usually not significantly affected by aliasing, we develop a novel and observable normalized leakage spectrum (NLS), which describes sensitively the effects of leaked red-noise power on the PSD at different temporal frequencies. Using Monte Carlo simulations, we demonstrate how an AGN underlying PSD sensitively determines the NLS when there is severe red-noise leakage and thereby how the NLS can be used to effectively constrain the underlying PSD.
Accepted by ApJ
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1604.07984
Hidden AGNs in Early-Type Galaxies
Alessandro Paggi1, Giuseppina Fabbiano1, Francesca Civano1,2, Silvia Pellegrini3, Martin Elvis1 and Dong-Woo Kim1
1. Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USA
2. Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121
3. Department of Astronomy, University of Bologna, via Ranzani 1, 40127 Bologna, Italy
We present a stacking analysis of the complete sample of Early Type Galaxies (ETGs) in the Chandra COSMOS (C-COSMOS) survey, to explore the nature of the X-ray luminosity in the redshift and stellar luminosity ranges 0<z<1.5 and 109<LK/L⊙<1013. Using established scaling relations, we subtract the contribution of X-ray binary populations, to estimate the combined emission of hot ISM and AGN. To discriminate between the relative importance of these two components, we (1) compare our results with the relation observed in the local universe LX,gas∝LK4.5 for hot gaseous halos emission in ETGs, and (2) evaluate the spectral signature of each stacked bin. We find two regimes where the non-stellar X-ray emission is hard, consistent with AGN emission. First, there is evidence of hard, absorbed X-ray emission in stacked bins including relatively high z (∼1.2) ETGs with average high X-ray luminosity (LX-LMXB ≳ 6×1042 erg/s). These luminosities are consistent with the presence of highly absorbed "hidden" AGNs in these ETGs, which are not visible in their optical-IR spectra and spectral energy distributions. Second, confirming the early indication from our C-COSMOS study of X-ray detected ETGs, we find significantly enhanced X-ray luminoaity in lower stellar mass ETGs (LK ≲ 1011L⊙), relative to the local LX,gas ∝ LK4.5 relation. The stacked spectra of these ETGs also suggest X-ray emission harder than expected from gaseous hot halos. This emission is consistent with inefficient accretion 10-5-10-4ṀEdd onto MBH∼106-108M⊙.
Accepted by ApJ
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1507.03170
Deadline: 31st May 2016
Further Information: https://jobs.itp.phys.ethz.ch/postdoc/
The Institute for Astronomy of the ETH Zurich invites applications for a two year postdoctoral position in the black hole group of Prof. Schawinski (http://www.astro.ethz.ch/schawinski) to work on active galaxies, galaxy-black hole co-evolution and the origin of black holes.
The successful candidate will be involved in the planning, execution and analysis of observational projects. Experience with any of: survey data, optical/NIR spectroscopy and radio/sub-mm data, would be a particular asset. There are also opportunities to get involved in citizen science projects, machine learning, and in the mentoring of students.
The position is initially for two years, but can be extended to a third year subject to funding. The salary scale is attractive (CHF 86'300 - 95'000) and there is substantial support for travel (observing, conference, collaboration), computing and publication charges. Switzerland is a full member of ESO and ESA. Zurich is regularly rated one of the top 10 cities of the world in terms of quality of life.
Applicants should have a PhD in astronomy or related field. The application should include a CV, publication list and a brief (3 pages max.) summary of past research and future research interests and should be uploaded to https://jobs.itp.phys.ethz.ch/postdoc/ by May 31, 2016. Three letters of reference should be uploaded, directly by the referees, to the same platform within the same deadline. The search will continue until the position is filled.
For further information, please contact Prof. Schawinski (firstname.lastname@example.org).
Deadline for Receipt of Proposals: 23:59:59 UT on 26th May 2016
e-MERLIN requests proposals from the international astronomical community for observations to be made during Cycle-4. Proposals are competitively peer-reviewed under standard STFC rules by the PATT e-MERLIN Time Allocation Committee. Allocation will be made on the basis of scientific merit and technical feasibility alone. During e-MERLIN operations ~50% of observing time has been allocated to large legacy projects and most of the remaining time will be allocated via PATT to standard proposals solicited prior to each observing semester.
e-MERLIN provides high resolution (12-150mas) and high sensitivity (~-14 microJy [inc. Lovell Telescope] in Cycle-4) imaging at cm wavelengths as well as polarimetry, spectroscopy and astrometry. Cycle-4 observations will commence in September 2016.
Developments during Cycle-4: Following testing and commissioning, the introduction of the full 2GHz bandwidth at C and K-Band is scheduled for delivery during the Cycle-4 observing period*. PATT observations made after this development may benefit from this extra bandwidth once it becomes available, however, this will be offered initially on a shared-risk basis. All proposals should be justified assuming the current available bandwidth of 512MHz. K-Band observations are also offered on a best-efforts basis. New K-Band receivers with improved sensitivity are being installed during Cycles 3 and 4.
Cycle-4 e-MERLIN Observations : September 2015 - January 2016
Deadline for Receipt of Proposals - 23:59:59 UT on 26th May 2016
Observing frequencies available:-
L-Band: 1.23GHz to 1.74GHz
C-Band: 4.5GHz to 7.5GHz
K-Band: 21GHz to 24GHz
Commencing in summer 2015, The University of Manchester is undertaking a 15 Million pounds upgrade programme on the JBO site including major work on the Lovell Telescope. As such during this e-MERLIN cycle there will be a limited availability of up to 10 days of the Lovell telescope for the inclusion within e-MERLIN PATT observations at L and C-band. Proposers must make a detailed case for the inclusion of the Lovell telescope in their proposed observations.
During Cycle-4, e-MERLIN C and K-Band operations utilising bandwidths wider than 512MHz will be on a best-efforts basis and no programmes are guaranteed. Proposals should assume 512MHz observing bandwidth. However, PIs of allocated proposals which may benefit from these enhanced capabilities will be informed and given the option to use these capabilities when they become available.
Proposers should consult the allocated e-MERLIN legacy programme to avoid conflicts (see notes below). In cases where PATT proposals directly replicate portions of allocated legacy projects, legacy projects will normally be given priority.
During Cycle-4 there is one VLBI session. Simultaneous joint VLBI+e-MERLIN observations are offered on a best efforts basis, and every effort will be made to provide simultaneous or contemporaneous matching e-MERLIN observations for joint programmes. EVN proposals should be submitted to the EVN Programme Committee - details for proposing for EVN time can be found via the EVN web pages.
More extensive technical details are available at e-MERLIN cycle-4 capabilities.
Proposals should be submitted via the e-MERLIN Web-based Northstar Proposal Tool. The proposal tool will be open for proposal submissions from 19th April 2016.