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. 226 -- August 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.
The MIXR sample: AGN activity versus star formation across the cross-correlation of WISE, 3XMM, and FIRST/NVSS.
B. Mingo1, M. G. Watson1, S. R. Rosen1, M. J. Hardcastle2, A. Ruiz3, A. Blain1, F. J. Carrera3, S. Mateos3, F.-X. Pineau4, and G. C. Stewart1
1. Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
2. School of Physics, Astronomy & Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
3. Instituto de Física de Cantabria (CSIC-UC), Avenida de los Castros, 39005 Santander, Spain
4. CNRS, Universitè de Strasbourg, Observatoire Astronomique, 11 rue de l'Universitè, 67000 Strasbourg, France
We cross-correlate the largest available Mid-Infrared (WISE), X-ray (3XMM) and Radio (FIRST+NVSS) catalogues to define the MIXR sample of AGN and star-forming galaxies. We pre-classify the sources based on their positions on the WISE colour/colour plot, showing that the MIXR triple selection is extremely effective to diagnose the star formation and AGN activity of individual populations, even on a flux/magnitude basis, extending the diagnostics to objects with luminosities and redshifts from SDSS DR12. We recover the radio/mid-IR star formation correlation with great accuracy, and use it to classify our sources, based on their activity, as radio-loud and radio-quiet AGN, LERGs/LINERs, and non-AGN galaxies. These diagnostics can prove extremely useful for large AGN and galaxy samples, and help develop ways to efficiently triage sources when data from the next generation of instruments becomes available. We study bias in detail, and show that while the widely-used WISE colour selections for AGN are very successful at cleanly selecting samples of luminous AGN, they miss or misclassify a substantial fraction of AGN at lower luminosities and/or higher redshifts. MIXR also allows us to test the relation between radiative and kinetic (jet) power in radio-loud AGN, for which a tight correlation is expected due to a mutual dependence on accretion. Our results highlight that long-term AGN variability, jet regulation, and other factors affecting the Q/Lbol relation, are introducing a vast amount of scatter in this relation, with dramatic potential consequences on our current understanding of AGN feedback and its effect on star formation.
Accepted by Monthly Notices of the Royal Astronomical Society DOI: http://dx.doi.org/10.1093/mnras/stw1826
E-mail contact: email@example.com
Preprint available at https://arxiv.org/abs/1607.06471
The Geometry of the Infrared and X-ray Obscurer in a Dusty Hyperluminous Quasar
Duncan Farrah1, Mislav Balokovic2, Daniel Stern3, Kathryn Harris1,4, Michelle Kunimoto5, Dominic J. Walton3, David M. Alexander6, Patricia Arévalo7, David R. Ballantyne8, Franz E. Bauer9,10,11,12, Steven Boggs13, William N. Brandt14,15,16, Murray Brightman2, Finn Christensen17, David L. Clements5, William Craig12,18, Andrew Fabian19, Charles Hailey13, Fiona Harrison2, Michael Koss21, George B. Lansbury6, Bin Luo22,23, Jennie Paine1, Sara Petty24, Kate Pitchford1, Claudio Ricci9,12, William Zhang25
1. Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA
2. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
3. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
4. Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife, Spain; Departamento de Astrofisica, Universidad de La Laguna (ULL), E-38205 La Laguna, Tenerife, Spain
5. Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK
6. Department of Physics, Durham University, Durham DH1 3LE, UK
7. Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretana N 1111, Playa Ancha, Valparaíso, Chile
8. Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332-0430, USA
9. Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
10. Millennium Institute of Astrophysics, MAS, Nuncio Monseñor Sótero Sanz 100, Providencia, Santiago de Chile
11. Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, Colorado 80301
12. EMBIGGEN Anillo, Concepción, Chile
13. Space Science Laboratory, University of California, Berkeley, CA 94720, USA
14. Department of Astronomy & Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802, USA
15. Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
16. Department of Physics, 104 Davey Lab, The Pennsylvania State University, University Park, PA 16802, USA
17. DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK - 2800 Lyngby, Denmark
18. Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
19. Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UK
20. Physics Department, Columbia University, New York, NY 10027, USA
21. Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland
22. School of Astronomy and Space Science, Nanjing University, Nanjing, 210093, China
23. Key laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, China
24. Green Science Policy Institute, Berkeley, CA 94709, USA
25. NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
We study the geometry of the AGN obscurer in IRAS, an IR-luminous, radio-intermediate FR-I source at z=0.442, using infrared data from Spitzer and Herschel, X-ray data from NuSTAR, Swift, Suzaku, and Chandra, and an optical spectrum from Palomar. The infrared data imply a total rest-frame 1-1000μm luminosity of 5.5×1046 ergs-1 and require both an AGN torus and starburst model. The AGN torus has an anisotropy-corrected IR luminosity of 4.9×1046 ergs-1, and a viewing angle and half opening angle both of approximately 36° from pole-on. The starburst has a star formation rate of (110±34)M⊙ yr-1 and an age of <50Myr. These results are consistent with two epochs of luminous activity in IRAS: one approximately 150Myr ago, and one ongoing. The X-ray data suggest a photon index of Γ ≃ 1.8 and a line-of-sight column of NH ≃ 5×1023 cm-2. This argues against a reflection-dominated hard X-ray spectrum, which would have implied a much higher NH and luminosity. The X-ray and infrared data are consistent with a bolometric AGN luminosity of Lbol∼(0.5-2.5)×1047 ergs-1. The X-ray and infrared data are further consistent with coaligned AGN obscurers in which the line of sight "skims" the torus. This is also consistent with the optical spectra, which show both coronal iron lines and broad lines in polarized but not direct light. Combining constraints from the X-ray, optical, and infrared data suggests that the AGN obscurer is within a vertical height of 20pc, and a radius of 125pc, of the nucleus.
Accepted by ApJ
E-mail contact: firstname.lastname@example.org
Preprint available at http://lanl.arxiv.org/abs/1606.05649
Far-infrared line spectra of active galaxies from the Herschel/PACS Spectrometer: the complete database
Juan Antonio Fernández-Ontiveros1, Luigi Spinoglio1, Miguel Pereira-Santaella2, Matthew A. Malkan3, Paola Andreani4, and Kalliopi M. Dasyra5,6
1. Istituto di Astrofisica e Planetologia Spaziali, INAF, Via Fosso del Cavaliere 100, I-00133 Roma, Italy
2. Centro de Astrobiología (CSIC/INTA), Ctra. de Torrejón a Ajalvir, km 4, E-28850 Torrejón de Ardoz, Madrid, Spain
3. Astronomy Division, University of California, Los Angeles, CA 90095-1547, USA
4. European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748, Garching, Germany
5. Department of Astrophysics, Astronomy & Mechanics, Faculty of Physics, University of Athens, Panepistimiopolis Zografos 15784, Greece
6. Observatoire de Paris, LERMA (CNRS:UMR8112), 61 Av. de l'Observatoire, F-75014, Paris, France
We present a coherent database of spectroscopic observations of far-IR fine-structure lines from the Herschel/PACS archive for a sample of 170 local AGN, plus a comparison sample of 20 starburst galaxies and 43 dwarf galaxies. Published Spitzer/IRS and Herschel/SPIRE line fluxes are included to extend our database to the full 10−600 μm spectral range. The observations are compared to a set of CLOUDY photoionisation models to estimate the above physical quantities through different diagnostic diagrams. We confirm the presence of a stratification of gas density in the emission regions of the galaxies, which increases with the ionisation potential of the emission lines. The new [OIV]25.9 μm/[OIII]88 μm vs [NEIII]15.6 μm/[NEII]12.8 μm diagram is proposed as the best diagnostic to separate: i) AGN activity from any kind of star formation; and ii) low-metallicity dwarf galaxies from starburst galaxies. Current stellar atmosphere models fail to reproduce the observed [OIV]25.9 μm/[OIII]88 μm ratios, which are much higher when compared to the predicted values. Finally, the ([NEIII]15.6 μm+[NEII]12.8 μm)/([SIV]10.5 μm+[SIII]18.7 μm) ratio is proposed as a promising metallicity tracer to be used in obscured objects, where optical lines fail to accurately measure the metallicity. The diagnostic power of mid- to far-infrared spectroscopy shown here for local galaxies will be of crucial importance to study galaxy evolution during the dust-obscured phase at the peak of the star formation and black-hole accretion activity (1 < z < 4). This study will be addressed by future deep spectroscopic surveys with present and forthcoming facilities such as JWST, ALMA, and SPICA.
Accepted by ApJS
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1607.02511
LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field
M.J. Hardcastle1, G. Gürkan1, R.J. van Weeren2, W.L. Williams1, P.N. Best3, F. de Gasperin4, D.A. Rafferty5, S.C. Read1, J. Sabater3, T.W. Shimwell4, D.J.B. Smith1, C. Tasse6, N. Bourne3, M. Brienza7,8, M. Brüggen5, G. Brunetti9, K.T. Chyzy10, J. Conway11, L. Dunne3,12, S.A. Eales10, S.J. Maddox3,12, M.J. Jarvis13,14, E.K. Mahony15,16, R. Morganti7,8, I. Prandoni9, H.J.A. Röttgering4, E. Valiante12 and G.J. White17,18
1. Centre for Astrophyics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
3. SUPA, Institute for Astronomy, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
4. Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, the Netherlands
5. University of Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
6. GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
7. ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo, The Netherlands
8. Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands
9. INAF-Institute of Radioastronomy, Via P. Gobetti 101, 40129, Bologna, Italy
10. Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków, Poland
11. Chalmers University of Technology, Onsala Space Observatory, S-43992, Sweden
12. School of Physics and Astronomy, Cardiff University, Queen's Buildings, The Parade, Cardiff CF24 3AA, UK
13. Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
14. Physics Department, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
15. Sydney Institute for Astronomy, School of Physics A28, The University of Sydney, NSW 2006, Australia
16. ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO)
17. Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
18. RAL Space, The Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0NL, UK
We present LOFAR High-Band Array (HBA) observations of the Herschel-ATLAS North Galactic Pole survey area. The survey we have carried out, consisting of four pointings covering around 142 square degrees of sky in the frequency range 126-173 MHz, does not provide uniform noise coverage but otherwise is representative of the quality of data to be expected in the planned LOFAR wide-area surveys, and has been reduced using recently developed `facet calibration' methods at a resolution approaching the full resolution of the datasets (∼10×6 arcsec) and an rms off-source noise that ranges from 100 μJy/beam in the centre of the best fields to around 2 mJy/beam at the furthest extent of our imaging. We describe the imaging, cataloguing and source identification processes, and present some initial science results based on a 5-σ source catalogue. These include (i) an initial look at the radio/far-infrared correlation at 150 MHz, showing that many Herschel sources are not yet detected by LOFAR; (ii) number counts at 150 MHz, including, for the first time, observational constraints on the numbers of star-forming galaxies; (iii) the 150-MHz luminosity functions for active and star-forming galaxies, which agree well with determinations at higher frequencies at low redshift, and show strong redshift evolution of the star-forming population; and (iv) some discussion of the implications of our observations for studies of radio galaxy life cycles.
Accepted by MNRAS
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1606.09437
Ensemble X-ray variability of active galactic nuclei. II. Excess variance and updated structure function
F. Vagnetti1, R. Middei1,2, M. Antonucci1, M. Paolillo3, and R. Serafinelli1
1. Dipartimento di Fisica, Università di Roma ``Tor Vergata'', Via della Ricerca Scientifica 1, I-00133, Roma, Italy
2. Dipartimento di Matematica e Fisica, Università Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
3. Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Via Cinthia 9, 80126 Napoli, Italy
Most investigations of the X-ray variability of active galactic nuclei (AGN) have been concentrated on the detailed analyses of individual, nearby sources. A relatively small number of studies have treated the ensemble behaviour of the more general AGN population in wider regions of the luminosity-redshift plane. We want to determine the ensemble variability properties of a rich AGN sample, called Multi-Epoch XMM Serendipitous AGN Sample (MEXSAS), extracted from the 5th release of the XMM-Newton Serendipitous Source Catalogue (XMMSSC-DR5), with redshift between ∼0.1 and ∼5, and X-ray luminosities in the 0.5-4.5 keV band between ∼1042 erg/s and ∼1047 erg/s. We urge caution on the use of the normalised excess variance (NXS), noting that it may lead to underestimate variability if used improperly. We use the structure function (SF), updating our previous analysis for a smaller sample. We propose a correction to the NXS variability estimator, taking account of the light curve duration in the rest frame on the basis of the knowledge of the variability behaviour gained by SF studies. We find an ensemble increase of the X-ray variability with the rest frame time lag τ, given by SF∝τ0.12. We confirm an inverse dependence on the X-ray luminosity, approximately as SF∝LX-0.19. We analyse the SF in different X-ray bands, finding a dependence of the variability on the frequency as SF∝ν-0.15, corresponding to a "softer when brighter" trend. In turn, this dependence allows us to parametrically correct the variability estimated in observer frame bands to that in the rest frame, resulting in a moderate (<15%) shift upwards (V-correction). Ensemble X-ray variability of AGNs is best described by the structure function. An improper use of the normalised excess variance may lead to an underestimate of the intrinsic variability, so that appropriate corrections to the data or the models must be applied to prevent these effects.
Accepted by A&A
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1607.02629
No Signatures of Black-Hole Spin in the X-ray Spectrum of the Seyfert 1 Galaxy Fairall 9
T. Yaqoob1,2, T. J. Turner2, M. M. Tatum2, M. Trevor2, and A. Scholtes2
1. Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
2. Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250
Fairall 9 is one of several type 1 active galactic nuclei for which it has been claimed that the angular momentum (or spin) of the supermassive black hole can be robustly measured, using the Fe Kα emission line and Compton-reflection continuum in the X-ray spectrum. The method rests upon the interpretation of the Fe Kα line profile and associated Compton-reflection continuum in terms of relativistic broadening in the strong gravity regime in the innermost regions of an accretion disc, within a few gravitational radii of the black hole. Here, we re-examine a Suzaku X-ray spectrum of Fairall 9 and show that a face-on toroidal X-ray reprocessor model involving only nonrelativistic and mundane physics provides an excellent fit to the data. The Fe Kα line emission and Compton reflection continuum are calculated self-consistently, the iron abundance is solar, and an equatorial column density of ∼1024 cm-2 is inferred. In this scenario, neither the Fe Kα line, nor the Compton-reflection continuum provide any information on the black-hole spin. Whereas previous analyses have assumed an infinite column density for the distant-matter reprocessor, the shape of the reflection spectrum from matter with a finite column density eliminates the need for a relativistically broadened Fe Kα line. We find a 90 per cent confidence range in the Fe Kα line FWHM of 1895-6205 km s-1, corresponding to a distance of ∼3100 to 33,380 gravitational radii from the black hole, or 0.015-0.49 pc for a black-hole mass of ∼1-3×108 M⊙.
Accepted by MNRAS
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1607.07125
Constraints on the Broad Line Region Properties and Extinction in Local Seyferts
Allan Schnorr-Müller1,2, R.I. Davies1, K.T. Korista3, L. Burtscher1, D. Rosario4, T. Storchi-Bergmann5, A. Contursi1, R. Genzel1, J. Graciá-Carpio1, E.K.S. Hicks6, A. Janssen1, M. Koss7, M.-Y. Lin1, D. Lutz1, W. Maciejewski8, F. Müller-Sánchez9, G. Orban de Xivry1, R. Riffel5, Rogemar A. Riffel10, M. Schartmann11, A. Sternberg12, E. Sturm1, L. Tacconi1, S. Veilleux13, O. A. Ulrich3
1. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, D-85741 Garching, Germany
2. CAPES Foundation, Ministry of Education of Brazil, 70040-020, Brasília, Brazil
3. Department of Physics, Western Michigan University, Kalamazoo, MI 49008-5252, USA
4. Centre of Extragalactic Astronomy, Department of Physics, Durham University, Durham, DH1 3LE, UK
5. Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS, Brazil
6. Physics & Astronomy Department, University of Alaska, Anchorage, AK 99508-4664, USA
7. Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland
8. Astrophysics Research Institute, Liverpool John Moores University, IC2 Liverpool Science Park, 146 Brownlow Hill, L3 5RF, UK
9. Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309-0389, USA
10. Departamento de Física, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
11. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
12. Raymond and Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Ramat Aviv 69978, Israel
13. Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742-2421 USA
We use high spectral resolution (R>8000) data covering 3800-13000Å to study the physical conditions of the broad line region (BLR) of nine nearby Seyfert 1 galaxies. Up to six broad HI lines are present in each spectrum. A comparison - for the first time using simultaneous optical to near-infrared observations - to photoionisation calculations with our devised simple scheme yields the extinction to the BLR at the same time as determining the density and photon flux, and hence distance from the nucleus, of the emitting gas. This points to a typical density for the HI emitting gas of 1011cm-3 and shows that a significant amount of this gas lies at regions near the dust sublimation radius, consistent with theoretical predictions. We also confirm that in many objects the line ratios are far from case B, the best-fit intrinsic broad-line Hα/Hβ ratios being in the range 2.5-6.6 as derived with our photoionization modeling scheme. The extinction to the BLR, based on independent estimates from HI and HeII lines, is AV≤3 for Seyfert 1-1.5s, while Seyfert 1.8-1.9s have AV in the range 4-8. A comparison of the extinction towards the BLR and narrow line region (NLR) indicates that the structure obscuring the BLR exists on scales smaller than the NLR. This could be the dusty torus, but dusty nuclear spirals or filaments could also be responsible. The ratios between the X-ray absorbing column NH and the extinction to the BLR are consistent with the Galactic gas-to-dust ratio if NH variations are considered.
Accepted by MNRAS.
E-mail contact: email@example.com
Preprint available at http://arxiv.org/abs/1607.07308
Star formation and AGN activity in the most luminous LINERs in the local universe
Mirjana Povic1, Isabel Márquez1, Hagai Netzer2, Josefa Masegosa1, Raanan Nordon2, Enrique Pérez1 and William Schoenell1
1. Instituto de Astrofísica de Andalucía (IAA-CSIC), Granada 18008, Spain
2. School of Physics and Astronomy and the Wise Observatory, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate LINERs at z=0.04-0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them. We measured emission line intensities, extinction, stellar populations, stellar masses, ages, AGN luminosities, and star-formation rates. We find considerable differences from other low-redshift LINERs, in terms of extinction, and general similarity to star forming (SF) galaxies. We confirm the existence of such luminous LINERs in the local universe, after being previously detected at z∼0.3 by Tommasin et al. (2012). The median stellar mass of these LINERs corresponds to 6-7×1010M⊙ which was found in previous work to correspond to the peak of relative growth rate of stellar populations and therefore for the highest SFRs. Other LINERs although showing similar AGN luminosities have lower SFR. We find that most of these sources have LAGN∼LSF suggesting co-evolution of black hole and stellar mass. In general the fraction of local LINERs on the main-sequence of SF galaxies is related to their AGN luminosity.
Accepted by MNRAS
E-mail contact: firstname.lastname@example.org, email@example.com
Preprint available at http://arXiv.org/abs/1607.03915
Extreme star formation events in quasar hosts over 0.5<z<4
Lura K. Pitchford1,2, Evanthia Hatziminaoglou1, Anna Feltre3, Duncan Farrah2, Charlotte Clarke4, Kathryn Harris2,5, Peter Hurley4, Sebastian Oliver4, Mathew Page6, Lingyu Wang7
1. ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
2. Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA
3. Sorbonne universités, UPMC-CNRS, UMR7095, Institut d'Astrophysique de Paris, F-75014, Paris, France
4. Astronomy Centre, Dept. of Physics & Astronomy, University of Sussex, Brighton BN1 9QH, UK
5. Instituto de Astrofísica de Canarias, C/via Láctea s/n, E-38205 La Laguna, Tenerife, Spain
6. Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
7. SRON Netherlands Institute for Space Research, Landleven 12, NL-9747 AD, Groningen, The Netherlands
We explore the relationship between active galactic nuclei and star formation in a sample of 513 optically luminous type 1 quasars up to redshifts of ∼4 hosting extremely high star formation rates (SFRs). The quasars are selected to be individually detected by the Herschel SPIRE instrument at >3σ at 250μm, leading to typical SFRs of order of 1000M⊙yr-1. We find the average SFRs to increase by almost a factor 10 from z∼0.5 to z∼3, mirroring the rise in the comoving SFR density over the same epoch. However, we find that the SFRs remain approximately constant with increasing accretion luminosity for accretion luminosities above 1012L⊙. We also find that the SFRs do not correlate with black hole mass. Both of these results are most plausibly explained by the existence of a self-regulation process by the starburst at high SFRs, which controls SFRs on time-scales comparable to or shorter than the AGN or starburst duty cycles. We additionally find that SFRs do not depend on Eddington ratio at any redshift, consistent with no relation between SFR and black hole growth rate per unit black hole mass. Finally, we find that high-ionisation broad absorption line (HiBAL) quasars have indistinguishable far-infrared properties to those of classical quasars, consistent with HiBAL quasars being normal quasars observed along a particular line of sight, with the outflows in HiBAL quasars not having any measurable effect on the star formation in their hosts.
Accepted by MNRAS
E-mail contact: firstname.lastname@example.org
Preprint available at http://arxiv.org/abs/1607.06459
Growth of supermassive black holes, galaxy mergers and supermassive binary black holes
S. Komossa1, J.G. Baker2, F.K. Liu3
1. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
2. NASA/GSFC, Mail Code: 663, Greenbelt, MD 20771, USA
3. Department of Astronomy, Peking University, Beijing 100871, China
The study of galaxy mergers and supermassive binary black holes (SMBBHs) is central to our understanding of the galaxy and black hole assembly and (co-)evolution at the epoch of structure formation and throughout cosmic history. Galaxy mergers are the sites of major accretion episodes, they power quasars, grow supermassive black holes (SMBHs), and drive SMBH-host scaling relations. The coalescing SMBBHs at their centers are the loudest sources of gravitational waves (GWs) in the universe, and the subsequent GW recoil has a variety of potential astrophysical implications which are still under exploration.Future GW astronomy will open a completely new window on structure formation and galaxy mergers, including the direct detection of coalescing SMBBHs, high-precision measurements of their masses and spins, and constraints on BH formation and evolution in the high-redshift universe.
Astronomy in Focus. Proceedings of the XXIXth IAU General Assembly, P. Benvenuti (ed).
E-mail contact: email@example.com
Preprint available at http://lanl.arxiv.org/abs/1606.06568
The location of the dust causing internal reddening of active galactic nuclei
Clio Z. P. Heard and C. Martin Gaskell
Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064
We use the Balmer decrements of the broad-line regions (BLRs) and narrow-line regions (NLRs) of active galactic nuclei (AGNs) as reddening indicators to investigate the location of the dust for four samples of AGNs with reliable estimates of the NLR contribution to the Balmer lines. Intercomparison of the NLR and BLR Balmer decrements indicates that the reddening of the NLR sets a lower limit to the reddening of the BLR. Almost no objects have high NLR reddening but low BLR reddening. The reddening of the BLR is often substantially greater than the reddening of the NLR. The BLR reddening is correlated with the equivalent widths of [OIII] lines and the intensity of the [OIII] lines relative to broad Hβ. We find these relationships to be consistent with the predictions of a simple model where the additional dust reddening the BLR is interior to the NLR. We thus conclude that the dust causing the additional reddening of the accretion disc and BLR is mostly located at a smaller radius than the NLR.
Accepted by MNRAS
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Preprint available at http://adsabs.harvard.edu/abs/2016arXiv160608914H
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Noordwijk (NL) and Madrid (E)
Deadline: 1 October 2015
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The European Space Agency awards several postdoctoral fellowships each year.
The aim of these fellowships is to provide young scientists, holding a PhD or the equivalent degree, with the means of performing space science research in fields related to the ESA Science and Robotic Exploration Programmes. Areas of research include planetary science, astronomy and astrophysics, solar and solar-terrestrial science, plasma physics and fundamental physics. The fellowships have a duration of two years and are tenable at the European Space Research and Technology Centre (ESTEC) in Noordwijk, Netherlands, or at the European Space Astronomy Centre (ESAC) in Villafranca del Castillo, near Madrid, Spain.
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Two Day workshop, Jodrell Bank Observatory 15-16th September 2016
The UK is taking a global leadership role in the SKA project. The HQ of the SKA Organization will be based in the UK at Jodrell Bank, and the UK is leading the international investment in the SKA.
e-MERLIN, the UK's National Radio Astronomy facility, and the 76-m Lovell Telescope constitute major radio astronomical facilities providing sub- arcsecond resolution imaging capabilities and state-of-the-art pulsar time- domain capabilities. Both are unique and world-class facilities and in combination have 25% of the collecting area of SKA1-mid with similar baseline and frequency coverage making them a powerful standalone instrument and pathfinder for SKA science.
We invite the UK's astronomical community to an open workshop discussing the latest science results from e-MERLIN and the Lovell telescopes and the development of a new integrated radio facility for the next era of Radio Astronomy.