DOCSLIB.ORG

Supernova Surroundings on Circumstellar and Galactic Scales

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Supernova Surroundings on Circumstellar and Galactic Scales Anders Nyholm Supernova surroundings on circumstellar and galactic scales Supernova surroundings on circumstellar and galactic scales on circumstellar and surroundings Supernova Anders Nyholm ISBN 978-91-7797-803-9 Department of Astronomy Doctoral Thesis in Astronomy at Stockholm University, Sweden 2019 Supernova surroundings on circumstellar and galactic scales Anders Nyholm Academic dissertation for the Degree of Doctor of Philosophy in Astronomy at Stockholm University to be publicly defended on Monday 23 September 2019 at 13.00 in sal FB42, AlbaNova universitetscentrum, Roslagstullsbacken 21. Abstract Some stars cease to be in a bright and destructive display called a supernova. This thesis explores what we can learn about supernovae (SNe) by studying their immediate surroundings, and what the SNe can teach us about their environments. The work presented is mostly based on the rich harvest of observations from 2009-2017 by the Palomar Transient Factory (PTF) and its successor, the intermediate PTF (iPTF). The PTF/iPTF was an untargeted sky survey at Palomar Observatory, aimed at finding and following up astronomical transients, such as SNe. During its existence, a massive star typically loses several solar masses of material. If much mass is lost in the decades or centuries before the SN, this material around the star (the circumstellar medium, CSM) will be quickly swept up by the ejecta of the eventual SN. This interaction can contribute strongly to the luminosity of the SN and make the light curve of an interacting SN carry signs of the progenitor star mass loss history. SNe with a hydrogen-rich CSM are called SNe Type IIn. A SN of this type, iPTF13z, found and followed by iPTF, had a slowly declining lightcurve with at least 5 major rebrightenings ("bumps") indicating rich structure in the CSM. Archival images clearly shows a precursor outburst about 210 days before the SN discovery, demonstrating the iPTF13z progenitor to be restless before its demise. Type IIn supernovae are heterogeneous, but only limited statistics has been done on samples. From PTF/iPTF, a sample of 42 SNe Type IIn was therefore selected, with photometry allowing their light curve rise times, decline rates and peak luminosities to be measured. It was shown that more luminous events are generally more long-lasting, but no strong correlation was found between rise times and peak luminosities. Two clusters of risetimes (around 20 and 50 days, respectively) were identified. The less long-lasting SNe Type IIn dominate the sample, suggesting that stars with a less extended dense CSM might be more common among SN Type IIn progenitors. Thermonuclear SNe (SNe Type Ia) are useful as standardisable candles, but no secure identification has yet been made of the progenitor system of a SN Type Ia. Using a late-time spectrum from the Nordic Optical Telescope of the nearby thermonuclear SN 2014J, a search for material ablated from a possible non-compact companion gave the upper limit of about 0.0085 solar masses of hydrogen-rich ablated gas. One likely explanation is that the SN 2014J progenitor system was a binary white dwarf. Supernovae are also useful tracers of the star formation history in their host galaxies, with SNe Type Ia tracing earlier epochs of star formation and exploding massive stars tracing more recent. For active galactic nuclei (AGN, the luminous centres of galaxies harbouring accreting supermassive black holes) SNe allows the so-called unification model to be tested. The unification model assumes that the main distinction between the two types of AGN is the viewing angle towards the central black hole, and that other properties (e.g. star formation history) of the host galaxies should be the same for the two AGN types. Matching 2190 SNe from PTF/iPTF to about 89000 AGN with spectra from the Sloan Digital Sky Survey, a significantly higher number of SNe in the hosts of AGN type 2 was found, challenging the unification model. Keywords: supernovae, circumstellar medium, SNe Type IIn, iPTF13z, intermediate Palomar Transient Factory, active galactic nuclei, SN 2014J. Stockholm 2019 http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-171451 ISBN 978-91-7797-803-9 ISBN 978-91-7797-804-6 Department of Astronomy Stockholm University, 106 91 Stockholm SUPERNOVA SURROUNDINGS ON CIRCUMSTELLAR AND GALACTIC SCALES Anders Nyholm Supernova surroundings on circumstellar and galactic scales Anders Nyholm ©Anders Nyholm, Stockholm University 2019 ISBN print 978-91-7797-803-9 ISBN PDF 978-91-7797-804-6 Cover image: Scenery with star trails, showing the dome of the 1.2 m Schmidt telescope (known as P48 or the Samuel Oschin Telescope) at Palomar Observatory, USA. After first light of P48 in 1948 and up until today, this venerable workhorse has been used for several important sky surveys, including the Palomar Transient Factory (PTF) and its successor, the intermediate PTF (iPTF). Papers II, III and IV in this thesis rely heavily on data from this telescope, obtained during PTF and iPTF. The image is cropped and used with permission. Photo credit: Palomar Observatory/California Institute of Technology Printed in Sweden by Universitetsservice US-AB, Stockholm 2019 Till Dasha List of included papers The four papers included in this PhD thesis will be referred to as Paper I, Paper II, Paper III and Paper IV. Their numeration is in chronological order. Summaries of the papers are given in Chapter 6. Paper I Lundqvist, P., Nyholm, A., Taddia, F., Sollerman, J., Johansson, J., Kozma, C., Lundqvist, N., Fransson, C., Garnavich, P. M., Kromer, M., Shappee, B. J. and Goobar, A. (2015). No trace of a single-degenerate companion in late spectra of supernovae 2011fe and 2014J. A&A, 577, A39. Paper II Villarroel, B., Nyholm, A., Karlsson, T., Comerón, S., Korn, A. J., Sollerman, J., and Zackrisson, E. (2017). AGN Luminosity and Stellar Age: Two Missing Ingredients for AGN Unification as Seen with iPTF Supernovae. ApJ, 837, 110V. Paper III Nyholm, A., Sollerman, J., Taddia, F., Fremling, C., Moriya, T. J., Ofek, E. O., Gal-Yam, A., De Cia, A., Roy, R., Kasliwal, M. M., Cao, Y., Nugent, P. E. and Masci, F. J. (2017). The bumpy light curve of Type IIn supernova iPTF13z over 3 years. A&A, 605, A6. Paper IV Nyholm, A., Sollerman, J., Tartaglia, L., Taddia, F., Fremling, C., Blagorodnova, N., Filippenko, A. V., Gal-Yam, A., Howell, D. A., Karamehmetoglu, E., Kulkarni, S. R., Laher, R., Masci, F., Leloudas, G., Kasliwal, M. M., Morå, K., Moriya, T. J., Ofek, E. O., Papadogiannakis, S., Quimby, R., Rebbapragada, U. and Schulze, S. (2019). Type IIn supernova light-curve properties measured from an untargeted survey sample. In review (A&A). Preprint: arXiv:1906.05812v1 Paper I, Paper III (©ESO) and Paper II (©AAS) reproduced with permission. Contributions of the author Contribution to Paper I: The author wrote the proposal to the Nordic Optical Telescope, manually reduced the spectrum of SN 2014J using IRAF (via PyRAF interface), wrote Section 2.2 in the paper, and contributed to the interpretation of the results. Lundqvist led the paper and the analysis. Contribution to Paper II: The author and Villarroel co-developed the idea (in the version applied here) to use supernovae for studying AGN hosts. The author provided the catalogue of PTF/iPTF supernovae, wrote and ran the computer scripts used to evaluate the presence of supernovae around AGN using the catalogues, wrote Sections 2.1, 2.2, 2.5 and 4.3 (Section 4.3.1 with contributions from Villarroel) and made Figure 3 in the paper, did the manual inspections mentioned in Sections 2.5 and 4.3.1, and contributed to the interpretation of the results. Karlsson did the statistical work. Contribution to Paper III: The author led the work on the paper and, from 2014, organised requests for photometry and spectra. The author wrote paper sections Abstract, 1, 2, 3.1, 3.2.3, 3.5, 3.6.1 and 4 (interpreting the results). A first, brief version of Section 3.6.2 was written by Moriya, then revised and expanded by the author (by e.g. adding the Monte Carlo experiment and making Figures 13 and 14 based on input from Moriya). The other sections were written together with Taddia. Figures 2, 5, 6 were drawn by the author. The remaining figures were prepared by Taddia and revised by the author. The photometry was obtained by Fremling from P48 and P60 images, as a part of his development of the FPIPE pipeline. Comments by Sollerman were incorporated in all parts of the paper. Contribution to Paper IV: The author initiated the project, selected the sample of supernovae, ran the PTFIDE pipeline for P48 photometry, wrote the manuscript (except for Appendix A and a part of Section 5.5) incorporating comments from co-authors, drew the figures (except Figures A.1 and A.2) and wrote a version of the NED distance calculator. Appendix A was written by Tartaglia (and modified by the author). Equation 3 and its adjacent text in Section 5.5 was written by Morå (who also wrote the script for the related statistical calculations). Karamehmetoglu helped developing the ∝ t2 rise time routine, Taddia assisted with figures, the cubic spline method and the Malmquist bias compensation. The GMM script used was by Papadogiannakis. Fremling ran FPIPE on P60 images. Re-use of material from the licentiate thesis of the author: Some of the introduction chapters of this PhD thesis (here called "P") are based on the introduction chapters of the author’s licentiate thesis (Nyholm, 2017, here called "L") as follows: P1 (L1), P1.1 (L1.1), P2 (L2), P2.1 (L2.1), P2.2 (L2.2 & L2.2.1), P2.3 (L2.3), P2.3.1 (L2.3.1), P2.3.2 (L2.3.2), P2.3.4 (L2.3.3), P2.3.5 (L2.3.4), P3 (L3), P3.1 (L3.1), P3.2 (L3.2), P4 (L3.3), P4.1 (L3.3.1), P4.2 (L3.3.2), P5 (L4), P5.1 (L4.1), P5.1.1 (L4.1.1), P5.2 (L4.2), P5.2.1 (L4.2.3), P5.3 (L4.2.2), P5.3.2 (L4.2.2), P5.3.3 (L4.2.2), P5.3.4 (L4.2.2), P5.3.5 (L4.4), P5.3.6 (L5.3.1 & L5.5.2), P5.4 (L4.3).
Load more

Recommended publications
  • Sky April 2011
    EDITORIAL ................. 2 ONE TO ONE WITH TONY MARSH 3 watcher CAPTION COMPETITION 7 April 2011 Sky OUTREACH EVENT AT CHANDLER SCHOOL .... 8 MOON AND SATURN WATCH 9 MY TELESCOPE BUILDING PROJECT 10 CONSTELLATION OF THE MONTH - VIRGO 15 OUTREACH AT BENTLEY COPSE 21 THE NIGHT SKY IN APRIL 22 Open-Air Planisphere taken by Adrian Lilly Page 1 © copyright 2011 guildford astronomical society www.guildfordas.org From the Editor Welcome to this, the April issue of Skywatcher. With the clocks going forward a hour the night sky has undergone a radical shift, the winter constellations are rapidly disappearing into the evening twilight, and the galaxy-filled reaches of Virgo are high up in the south and well-placed for observation. But I digress, whatever telescope you own or have stashed away at the back of the garage, the thought of making your own has probably crossed your mind at some point. I‟m delighted to have an article from Jonathan Shinn describing how he built a 6-inch Dobsonian – including grinding the mirror! Our lead-off article this issue is the interview from Brian Gordon-States with Tony Marsh. Tony has been a Committee member for many years, and much like previous interviews the story behind how he became fascinated with Astronomy is a compelling one. If there is a theme to this issue it‟s probably one of Outreach as I have two reports to share with you all. These events give youngsters the chance to look through a telescope at the wonders of the universe, and our closer celestial neighbours with someone on-hand to explain what they are looking at.
    [Show full text]
  • Luminous Blue Variables
    Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs.
    [Show full text]
  • Curriculum Vitae Avishay Gal-Yam
    January 27, 2017 Curriculum Vitae Avishay Gal-Yam Personal Name: Avishay Gal-Yam Current address: Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel. Telephones: home: 972-8-9464749, work: 972-8-9342063, Fax: 972-8-9344477 e-mail: [email protected] Born: March 15, 1970, Israel Family status: Married + 3 Citizenship: Israeli Education 1997-2003: Ph.D., School of Physics and Astronomy, Tel-Aviv University, Israel. Advisor: Prof. Dan Maoz 1994-1996: B.Sc., Magna Cum Laude, in Physics and Mathematics, Tel-Aviv University, Israel. (1989-1993: Military service.) Positions 2013- : Head, Physics Core Facilities Unit, Weizmann Institute of Science, Israel. 2012- : Associate Professor, Weizmann Institute of Science, Israel. 2008- : Head, Kraar Observatory Program, Weizmann Institute of Science, Israel. 2007- : Visiting Associate, California Institute of Technology. 2007-2012: Senior Scientist, Weizmann Institute of Science, Israel. 2006-2007: Postdoctoral Scholar, California Institute of Technology. 2003-2006: Hubble Postdoctoral Fellow, California Institute of Technology. 1996-2003: Physics and Mathematics Research and Teaching Assistant, Tel Aviv University. Honors and Awards 2012: Kimmel Award for Innovative Investigation. 2010: Krill Prize for Excellence in Scientific Research. 2010: Isreali Physical Society (IPS) Prize for a Young Physicist (shared with E. Nakar). 2010: German Federal Ministry of Education and Research (BMBF) ARCHES Prize. 2010: Levinson Physics Prize. 2008: The Peter and Patricia Gruber Award. 2007: European Union IRG Fellow. 2006: “Citt`adi Cefal`u"Prize. 2003: Hubble Fellow. 2002: Tel Aviv U. School of Physics and Astronomy award for outstanding achievements. 2000: Colton Fellow. 2000: Tel Aviv U. School of Physics and Astronomy research and teaching excellence award.
    [Show full text]
  • Formation and Evolution of Stars
    Journal of Physical Science and Application 11 (1) (2021) 1-11 doi: 10.17265/2159-5348/2021.01.001 D DAVID PUBLISHING Formation and Evolution of Stars Cuixiang Zhong Department of Physics, Jiangxi Normal University, Nanchang, China Abstract: The evolution of stars is one of the most important problems in astrophysics. However, the existing theories of stellar evolution fail to reveal the real mechanism of star formation, and thus fail to correctly reveal the mechanisms and laws of star growth, aging, death and resurrection. Therefore, by studying the formation process of satellites, planets and stars, the author can reveal the mechanisms and laws of star formation and evolution: as the star spins rapidly and its planets go round and round, a series of cyclones can form all over the star. These cyclones not only ignite thermonuclear reactions in the star, but also continuously absorb hydrogen and other interstellar material in space to maintain thermonuclear reactions in the star. But, with the increase of star mass, if the magnetic attraction of the stellar cyclone grows large enough that the star engulfs the innermost planet scattering cyclones through the magnetic attraction of the cyclone, the stellar mass will increase significantly, the stellar atmosphere will thicken significantly, the internal temperature of the star will increase greatly, and the huge energy will be released, causing the star to suddenly expand and become a red giant. When the red giant burns the swallowed planet, its internal temperature will gradually decrease, and the helium fusion will stop. At this time, the central gravity of the star cannot be balanced by the radiation pressure generated by the hydrogen or helium fusion, and the inner star will contract.
    [Show full text]
  • Snhunt151: an Explosive Event Inside a Dense Cocoon
    MNRAS 475, 2614–2631 (2018) doi:10.1093/mnras/sty009 Advance Access publication 2018 January 9 SNhunt151: an explosive event inside a dense cocoon N. Elias-Rosa,1,2‹ S. Benetti,1 E. Cappellaro,1 A. Pastorello,1 G. Terreran,1 A. Morales-Garoffolo,2 S. C. Howerton,3 S. Valenti,4 E. Kankare,5 A. J. Drake,6 S. G. Djorgovski,6 L. Tomasella,1 L. Tartaglia,1,7 T. Kangas,8 P. Ochner,1 Downloaded from https://academic.oup.com/mnras/article-abstract/475/2/2614/4795309 by Universidad Andres Bello user on 22 April 2019 A. V. Filippenko,9,10 F. Ciabattari,11 S. Geier,12,13 D. A. Howell,14,15 J. Isern,2 S. Leonini,16 G. Pignata17,18 and M. Turatto1 1INAF – Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, I-35122 Padova, Italy 2Department of Applied Physics, University of Cadiz,´ Campus of Puerto Real, E-11510 Cadiz,´ Spain 31401 South A, Arkansas City, KS 67005, USA 4Department of Physics, University of California, Davis, CA 95616, USA 5Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, UK 6Astronomy Department, California Institute of Technology, Pasadena, CA 91125, USA 7Department of Astronomy and Steward Observatory, University of Arizona, 933 N Cherry Ave, Tucson, AZ 85719, USA 8Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Vais¨ al¨ antie¨ 20, FI-21500 Piikkio,¨ Finland 9Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA 10Miller Senior Fellow, Miller Institute for Basic Research in Science, University of California,
    [Show full text]
  • Arxiv:0709.0302V1 [Astro-Ph] 3 Sep 2007 N Ro,M,414 USA 48104, MI, Arbor, Ann USA As(..Mcayne L 01.Sc Aeilcudslow Could Material Such Some 2001)
    DRAFT VERSION NOVEMBER 4, 2018 Preprint typeset using LATEX style emulateapj v. 03/07/07 SN 2005AP: A MOST BRILLIANT EXPLOSION ROBERT M. QUIMBY1,GREG ALDERING2,J.CRAIG WHEELER1,PETER HÖFLICH3,CARL W. AKERLOF4,ELI S. RYKOFF4 Draft version November 4, 2018 ABSTRACT We present unfiltered photometric observations with ROTSE-III and optical spectroscopic follow-up with the HET and Keck of the most luminous supernova yet identified, SN 2005ap. The spectra taken about 3 days before and 6 days after maximum light show narrow emission lines (likely originating in the dwarf host) and absorption lines at a redshift of z =0.2832, which puts the peak unfiltered magnitude at −22.7 ± 0.1 absolute. Broad P-Cygni features corresponding to Hα, C III,N III, and O III, are further detected with a photospheric velocity of ∼ 20,000kms−1. Unlike other highly luminous supernovae such as 2006gy and 2006tf that show slow photometric evolution, the light curve of SN 2005ap indicates a 1-3 week rise to peak followed by a relatively rapid decay. The spectra also lack the distinct emission peaks from moderately broadened (FWHM ∼ 2,000kms−1) Balmer lines seen in SN 2006gyand SN 2006tf. We briefly discuss the origin of the extraordinary luminosity from a strong interaction as may be expected from a pair instability eruption or a GRB-like engine encased in a H/He envelope. Subject headings: Supernovae, SN 2005ap 1. INTRODUCTION the ultra-relativistic flow and thus mask the gamma-ray bea- Luminous supernovae (SNe) are most commonly associ- con announcing their creation, unlike their stripped progeni- ated with the Type Ia class, which are thought to involve tor cousins.
    [Show full text]
  • 9905625.PDF (3.665Mb)
    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 typewriter free, while others may be from any type o f 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 afreet reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are m is^ g pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., m ^ s, drawings, charts) are reproduced by sectioning the orignal, begnning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. KGgher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Infoimation Compaiy 300 North Zeeb Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 UNIVERSITY OF OKLAHOMA GRADUATE COLLEGE “ ‘TIS SOMETHING, NOTHING”, A SEARCH FOR RADIO SUPERNOVAE A DISSERTATION SUBMITTED TO THE GRADUATE FACULTY in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY By CHRISTOPHER R.
    [Show full text]
  • Formation of Dust and Molecules in Supernovae
    2019/02/06 Formation of dust and molecules in supernovae Takaya Nozawa (National Astronomical Observatory of Japan) SN 1987A Cassiopeia A SNR 0509-67.5 1-1. Introduction Question : Can supernovae (SNe) produce molecules and dust grains? Nozawa 2014, Astronomical Herald 2-1. Thermal emission from dust in SN 1987A light curve 60day 200day (optical luminosity) 415day 615day Whitelock+89 - dust starts to form in the 755day ejecta at ~400 days - dust mass ay 775 day: > ~10-4 Msun (optically thin assumed) Wooden+93 2-2. CO and SiO detection in SN 1987A CO first overtone: 2.29-2.5 μm 97 day CO fundamental: 4.65-6.0 μm SiO fundamental: 7.6-9.5 μm 200day SN Ic 2000ew, Gerardy+2002 415day 615day 58 day 755day SN II-pec 1987A, Wooden+1993 SN II-P 2016adj, Banerjee+2018 2-3. CO and SiO masses in SN 1987A CO Gerardy+2002, see also Banerjee+2018 Liu+95 ‐CO emission is seen in various SiO types of CCSNe from ~50 day ‐CO/SiO masses in SN 1987A Mco > ~4x10-3 Msun MSiO > ~7x10-4 Msun Liu & Dalgarno 1996 2-4. Dust mass in Cassiopeia A (Cas A) SNR ○ Estimated mass of dust in Cas A ・ warm/hot dust (80-300K) (3-7)x10-3 Msun (IRAS, Dwek et al. 1987) ~7.7x10-5 Msun (ISO, Arendt et al. 1999) 0.02-0.054 Msun (Spitzer, Rho+2008) ➜ Mdust = 10-4-10-2 Msun consistent with >10-4 Msun in SN 1987A Dwek+1987, IRAS Rho+2008 Spitzer Arendt+1999, ISO 3-1.
    [Show full text]
  • Iptf14hls: a Unique Long-Lived Supernova from a Rare Ex- Plosion Channel
    iPTF14hls: A unique long-lived supernova from a rare ex- plosion channel I. Arcavi1;2, et al. 1Las Cumbres Observatory Global Telescope Network, Santa Barbara, CA 93117, USA. 2Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA. 1 Most hydrogen-rich massive stars end their lives in catastrophic explosions known as Type 2 IIP supernovae, which maintain a roughly constant luminosity for ≈100 days and then de- 3 cline. This behavior is well explained as emission from a shocked and expanding hydrogen- 56 4 rich red supergiant envelope, powered at late times by the decay of radioactive Ni produced 1, 2, 3 5 in the explosion . As the ejected mass expands and cools it becomes transparent from the 6 outside inwards, and decreasing expansion velocities are observed as the inner slower-moving 7 material is revealed. Here we present iPTF14hls, a nearby supernova with spectral features 8 identical to those of Type IIP events, but remaining luminous for over 600 days with at least 9 five distinct peaks in its light curve and expansion velocities that remain nearly constant in 10 time. Unlike other long-lived supernovae, iPTF14hls shows no signs of interaction with cir- 11 cumstellar material. Such behavior has never been seen before for any type of supernova 12 and it challenges all existing explosion models. Some of the properties of iPTF14hls can be 13 explained by the formation of a long-lived central power source such as the spindown of a 4, 5, 6 7, 8 14 highly magentized neutron star or fallback accretion onto a black hole .
    [Show full text]
  • A Search for Runaway Stars in Twelve Galactic Supernova Remnants†
    Received 09 November 2020; Revised –; Accepted 07 December 2020 DOI: xxx/xxxx ORIGINAL ARTICLE A search for runaway stars in twelve Galactic supernova remnants£ Oliver Lux* | Ralph Neuhäuser | Markus Mugrauer | Richard Bischoff Astrophysical Institute and University Observatory, Friedrich Schiller University Jena, Thuringia, Germany Runaway stars can result from core-collapse supernovae in multiple stellar systems. If the supernova disrupts the system, the companion gets ejected with its former Correspondence *Oliver Lux, Schillergäßchen 2, 07745 Jena. orbital velocity. A clear identification of a runaway star can yield the time and place Email: [email protected] of the explosion as well as orbital parameters of the pre-supernova binary system. Previous searches have mostly considered O- and B-type stars as runaway stars because they are always young in absolute terms (not much older than the lifetime of the progenitor) and can be detected up to larger distances. We present here a search for runaway stars of all spectral types. For late-type stars, a young age can be inferred from the lithium test. We used Gaia data to identify and characterise runaway star candidates in nearby supernova remnants, obtained spectra of 39 stars with UVES at the VLT and HDS at the Subaru telescope and found a significant amount of lithium in the spectra of six dwarf stars. We present the spectral analysis, including measure- ments of radial velocities, atmospheric parameters and lithium abundances. Then we estimate the ages of our targets from the Hertzsprung-Russell diagram and with the lithium test, present a selection of promising runaway star candidates and draw constraints on the number of ejected runaway stars compared to model expectations.
    [Show full text]
  • A Magnetar Model for the Hydrogen-Rich Super-Luminous Supernova Iptf14hls Luc Dessart
    A&A 610, L10 (2018) https://doi.org/10.1051/0004-6361/201732402 Astronomy & © ESO 2018 Astrophysics LETTER TO THE EDITOR A magnetar model for the hydrogen-rich super-luminous supernova iPTF14hls Luc Dessart Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile e-mail: [email protected] Received 2 December 2017 / Accepted 14 January 2018 ABSTRACT Transient surveys have recently revealed the existence of H-rich super-luminous supernovae (SLSN; e.g., iPTF14hls, OGLE-SN14-073) that are characterized by an exceptionally high time-integrated bolometric luminosity, a sustained blue optical color, and Doppler- broadened H I lines at all times. Here, I investigate the effect that a magnetar (with an initial rotational energy of 4 × 1050 erg and 13 field strength of 7 × 10 G) would have on the properties of a typical Type II supernova (SN) ejecta (mass of 13.35 M , kinetic 51 56 energy of 1:32 × 10 erg, 0.077 M of Ni) produced by the terminal explosion of an H-rich blue supergiant star. I present a non-local thermodynamic equilibrium time-dependent radiative transfer simulation of the resulting photometric and spectroscopic evolution from 1 d until 600 d after explosion. With the magnetar power, the model luminosity and brightness are enhanced, the ejecta is hotter and more ionized everywhere, and the spectrum formation region is much more extended. This magnetar-powered SN ejecta reproduces most of the observed properties of SLSN iPTF14hls, including the sustained brightness of −18 mag in the R band, the blue optical color, and the broad H I lines for 600 d.
    [Show full text]
  • Fundamental Properties of Core-Collapse Supernova and GRB Progenitors: Predicting the Look of Massive Stars Before Death
    A&A 558, A131 (2013) Astronomy DOI: 10.1051/0004-6361/201321906 & c ESO 2013 Astrophysics Fundamental properties of core-collapse supernova and GRB progenitors: predicting the look of massive stars before death Jose H. Groh1, Georges Meynet1, Cyril Georgy2, and Sylvia Ekström1 1 Geneva Observatory, Geneva University, Chemin des Maillettes 51, 1290 Sauverny, Switzerland e-mail: [email protected] 2 Astrophysics group, EPSAM, Keele University, Lennard-Jones Labs, ST5 5BG Keele, UK Received 16 May 2013 / Accepted 20 August 2013 ABSTRACT We investigate the fundamental properties of core-collapse supernova (SN) progenitors from single stars at solar metallicity. For this purpose, we combine Geneva stellar evolutionary models with initial masses of Mini = 20−120 M with atmospheric and wind models using the radiative transfer code CMFGEN. We provide synthetic photometry and high-resolution spectra of hot stars at the pre-SN stage. For models with Mini = 9−20 M, we supplement our analysis using publicly available MARCS model atmospheres of RSGs to estimate their synthetic photometry. We employ well-established observational criteria of spectroscopic classification and find that, depending on their initial mass and rotation, massive stars end their lives as red supergiants (RSG), yellow hypergiants (YHG), luminous blue variables (LBV), and Wolf-Rayet (WR) stars of the WN and WO spectral types. For rotating models, we obtained the + following types of SN progenitors: WO1–3 (Mini ≥ 32 M), WN10–11 (25 < Mini < 32 M), LBV (20 ≤ Mini ≤ 25 M), G1 Ia (18 < Mini < 20 M), and RSGs (9 ≤ Mini ≤ 18 M). For non-rotating models, we found spectral types WO1–3 (Mini > 40 M), WN7–8 (25 < Mini ≤ 40 M), WN11h/LBV (20 < Mini ≤ 25 M), and RSGs (9 ≤ Mini ≤ 20 M).
    [Show full text]