182 results found
Mattila S, Pérez-Torres M, Efstathiou A, et al., 2018, A dust-enshrouded tidal disruption event with a resolved radio jet in a galaxy merger, Science, Vol: 361, Pages: 482-485, ISSN: 0036-8075
Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 1052 erg in the infrared and radio but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.
Kankare E, Kotak R, Mattila S, et al., 2017, A population of highly energetic transient events in the centres of active galaxies, Nature Astronomy, Vol: 1, Pages: 865-871, ISSN: 2397-3366
Recent all-sky surveys have led to the discovery of new types of transients. These include stars disrupted by the central supermassive black hole, and supernovae that are 10–100 times more energetic than typical ones. However, the nature of even more energetic transients that apparently occur in the innermost regions of their host galaxies is hotly debated1,2,3. Here we report the discovery of the most energetic of these to date: PS1-10adi, with a total radiated energy of ~2.3 × 1052 erg. The slow evolution of its light curve and persistently narrow spectral lines over ∼ 3 yr are inconsistent with known types of recurring black hole variability. The observed properties imply powering by shock interaction between expanding material and large quantities of surrounding dense matter. Plausible sources of this expanding material are a star that has been tidally disrupted by the central black hole, or a supernova. Both could satisfy the energy budget. For the former, we would be forced to invoke a new and hitherto unseen variant of a tidally disrupted star, while a supernova origin relies principally on environmental effects resulting from its nuclear location. Remarkably, we also discover that PS1-10adi is not an isolated case. We therefore surmise that this new population of transients has previously been overlooked due to incorrect association with underlying central black hole activity.
Wang X, Wang L, Filippenko AV, et al., 2012, EVIDENCE FOR TYPE Ia SUPERNOVA DIVERSITY FROM ULTRAVIOLET OBSERVATIONS WITH THE HUBBLE SPACE TELESCOPE, ASTROPHYSICAL JOURNAL, Vol: 749, ISSN: 0004-637X
Mattila S, Lundqvist P, Groningsson P, et al., 2010, ABUNDANCES AND DENSITY STRUCTURE OF THE INNER CIRCUMSTELLAR RING AROUND SN 1987A, ASTROPHYSICAL JOURNAL, Vol: 717, Pages: 1140-1156, ISSN: 0004-637X
Hunter DJ, Valenti S, Kotak R, et al., 2009, Extensive optical and near-infrared observations of the nearby, narrow-lined type Ic SN 2007gr: days 5 to 415, ASTRONOMY & ASTROPHYSICS, Vol: 508, Pages: 371-389, ISSN: 0004-6361
Botticella MT, Pastorello A, Smartt SJ, et al., 2009, SN 2008S: an electron-capture SN from a super-AGB progenitor?, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 398, Pages: 1041-1068, ISSN: 0035-8711
Hillebrandt W, and55others, 2009, Division VIII / Working Group Supernova, Reports on Astronomy 2006-2009, Publisher: Cambridge University Press, 2009, Transactions IAU, Volume 4, Issue 27A
The Supernova Working Group was re-established at the IAU XXV General Assembly in Sydney, 21 July 2003, sponsored by Commissions 28 (Galaxies) and 47 (Cosmology). Here we report on some of its activities since 2005.
Trundle C, Kotak R, Vink JS, et al., 2009, Can LBV's Be The Direct Progenitors of Core Collapse Supernovae?001, International Conference on Probing Stellar Populations Out to the Distant Universe, Publisher: AMER INST PHYSICS, Pages: 311-+, ISSN: 0094-243X
Mattila S, Meikle WPS, Lundqvist P, et al., 2008, Massive stars exploding in a He-rich circumstellar medium - III. SN 2006jc: infrared echoes from new and old dust in the progenitor CSM, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 389, Pages: 141-155, ISSN: 0035-8711
Pignata G, Benetti S, Mazzali PA, et al., 2008, Optical and infrared observations of SN 2002dj: some possible common properties of fast-expanding Type Ia supernovae, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 388, Pages: 971-990, ISSN: 0035-8711
Trundle C, Kotak R, Vink JS, et al., 2008, SN 2005 gj: evidence for LBV supernovae progenitors?, ASTRONOMY & ASTROPHYSICS, Vol: 483, Pages: L47-L50, ISSN: 0004-6361
Meikle WPS, Mattila S, Pastorello A, et al., 2007, A Spitzer Space Telescope Study of SN 2003gd: Still No Direct Evidence that Core-Collapse Supernovae are Major Dust Factories, Astrophysical Journal, Vol: 665, Pages: 608-617
We present a new, detailed analysis of late-time mid-infrared observations of the Type II-P supernova (SN) 2003gd. At about 16 months after the explosion, the mid-IR flux is consistent with emission from 4×10-5 Msolar of newly condensed dust in the ejecta. At 22 months emission from pointlike sources close to the SN position was detected at 8 and 24 μm. By 42 months the 24 μm flux had faded. Considerations of luminosity and source size rule out the ejecta of SN 2003gd as the main origin of the emission at 22 months. A possible alternative explanation for the emission at this later epoch is an IR echo from preexisting circumstellar or interstellar dust. We conclude that, contrary to the claim of Sugerman and coworkers, the mid-IR emission from SN 2003gd does not support the presence of 0.02 Msolar of newly formed dust in the ejecta. There is, as yet, no direct evidence that core-collapse supernovae are major dust factories.
Stanishev V, Goobar A, Benetti S, et al., 2007, SN2003du: 480 days in the life of a normal type Ia supernova, ASTRONOMY & ASTROPHYSICS, Vol: 469, Pages: 645-U201, ISSN: 0004-6361
Gerardy CL, Meikle WPS, Kotak R, et al., 2007, Signatures of delayed detonation, asymmetry, and electron capture in the mid-infrared spectra of supernovae 2003hv and 2005df, ASTROPHYSICAL JOURNAL, Vol: 661, Pages: 995-1012, ISSN: 0004-637X
Pastorello A, Mazzali PA, Pignata G, et al., 2007, ESC and KAIT observations of the transitional type Ia SN 2004eo, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 377, Pages: 1531-1552, ISSN: 0035-8711
Mattila S, Meikle W, Greimel R, et al., 2007, Obscured Supernovae in Starburst Galaxies, Galaxy Evolution Across the Hubble Time, Pages: 323-323
bout one core-collapse supernova is expected to explode every 5-10 years in the nuclear regions of M 82 and other nearby starburst galaxies. Furthermore, in luminous infrared galaxies such as the interacting system Arp 299 (NGC 3690 + IC 0694) at least one core-collapse supernova can be expected every year. Due to the high dust extinction most of these supernovae have remained undetected. However, in the past few years, a number of nearby supernovae with relatively high host galaxy extinctions (AV ̃ 5) have been detected. Searches working at optical wavelengths have been able to detect a couple of highly obscured events within ̃5 Mpc, and near-infrared searches a few more at distances up to ̃50 Mpc. Here I show results from two near-infrared Ks-band searches we have recently carried out using the William Herschel Telescope and the Naos Conica Adaptive Optics System on the Very Large Telescope to discover obscured supernovae within the nuclear regions of nearby starburst galaxies and luminous infrared galaxies. I also review the results from other infrared supernova searches, and discuss the future of searches at these wavelengths.
Mattila S, Vaisanen P, Farrah D, et al., 2007, Adaptive optics discovery of supernova 2004ip in the nuclear regions of the luminous infrared galaxy IRAS 18293-3413, ASTROPHYSICAL JOURNAL, Vol: 659, Pages: L9-L12, ISSN: 0004-637X
Mattila S, Vaisanen P, Meikle W, et al., 2007, Supernova 2004ip in IRAS 18293-3413 = Psn K0409-001, Central Bureau Electronic Telegrams, 858
S. Mattila, Queen's University Belfast, and his colleagues (P. Vaisanen, P. Meikle, T. Dahlen, A. Efstathiou, D. Farrah, C. Fransson, P. Lira, P. Lundqvist, G. Ostlin, S. Ryder, and J. Sollerman) report the discovery of an apparent supernova in K_s-band images obtained using the NAOS CONICA adaptive optics system on the European Southern Observatory's Very Large Telescope (VLT). The new object was first observed on 2004 Sept. 13.1 UT and Sept. 15.0 at K_s = 18.7 +/- 0.1, and again on Sept. 27.1 UT at K_s = 18.9 +/- 0.15. SN 2004ip, which was designated PSN K0409-001 by the Central Bureau in September 2004 (and posted at http://cfa-www.harvard.edu/iau/CBAT_PSN.html), is located within the nuclear regions of the luminous infrared galaxy (LIRG) IRAS 18293-3413 at R.A. = 18h32m41s.26, Decl. = -34o11'26".7 (equinox 2000.0), which is 1".14 east and 0".78 north of (or 500 pc from) the galaxy's Ks-band nucleus. The apparent supernova was detected via image-subtraction techniques using a reference K_s-band image obtained under similar conditions on 2004 May 4.3 with the VLT/NACO as part of a search campaign for highly obscured supernovae. Its luminosity and light curve are consistent with a core-collapse event with a likely extinction of between about 5 and 40 magnitudes in V (Mattila et al. 2007, astro-ph/0702591). Mattila adds that explanations other than a supernova for this object are extremely unlikely. SN 2004ip is located within a circumnuclear starburst of its host galaxy which has an infrared SED consistent with no contribution from an active-galactic nucleus (AGN). Also, Mannucci et al. (2003, A.Ap. 401, 519) monitored IRAS 18293-3413 in K_s-band for 2.5 years, finding no variability within the nuclear regions. A line-of-sight variable foreground star superimposed on the central-kiloparsec regions of this galaxy (a search area of only about 8 square arcsec) is considered highly unlikely, such stars have not been observed elsewhere in the observation
Meikle WPS, Pozzo M, 2007, Erratum: Optical and infrared observations of the Type IIP SN 2002hh from days 3 to 397, MNRAS
Pozzo M, Meikle WPS, Rayner JT, et al., 2007, Erratum: Optical and infrared observations of the Type IIP SN 2002hh from days 3 to 397, Monthly Notices of the Royal Astronomical Society, Vol: 375, Pages: 416-416, ISSN: 0035-8711
Kotak R, Meikle P, Pozzo M, et al., 2006, Spitzer measurements of atomic and molecular abundances in the Type IIPSN 2005af, ASTROPHYSICAL JOURNAL, Vol: 651, Pages: L117-L120, ISSN: 0004-637X
Taubenberger S, Pastorello A, Mazzali PA, et al., 2006, SN 2004aw: confirming diversity of Type Ic supernovae, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 371, Pages: 1459-1477, ISSN: 0035-8711
Meikle WPS, Mattila S, Gerardy CL, et al., 2006, A Spitzer space telescope study of Sn 2002hh: An infrared echo from a Type IIP supernova, ASTROPHYSICAL JOURNAL, Vol: 649, Pages: 332-344, ISSN: 0004-637X
Gerardy C, Meikle W, Hoeflich P, et al., 2006, Infrared Spectroscopy of Thermonuclear Supernovae, Supernovae: One Millennium After SN1006
Infrared spectroscopy is a powerful new tool which is yielding unique new insights into the physics of thermonuclear (Type Ia) supernovae. Photospheric era near-infrared (NIR) specta are less hampered by line-blending than optical spectra, allowing for the direct measurement of the kinematic distribution of chemical species in the ejecta. Results indicate a highly layered chemical structure and are roughly in line with the predictions of Delayed-Detonation (DD) models of SNe Ia. Late-time (200 d+) NIR spectra of SNe Ia are dominated by relatively strong but optically thin [Fe II] lines, which can trace out the global distribution of radioactive ejecta. Preliminary results suggest that many (perhaps most) SNe Ia show bulk offsets in the [Fe II] features of up to ~2500 km/s. Such shifts in the kinematic distribution of radioactive ejecta might be the signature of off-center detonations. Late time NIR spectra also show that at least some SNe Ia exhibit boxy [Fe II] line profiles, indicative of a central hole in the radioactive ejecta. Such profiles can be explained as the result of high-density nuclear burning creating stable Ni and Fe in the earliest burning phases. This interpretation is supported by the discovery of significant emission from stable Ni in mid-IR spectra obtained by the MISC collaboration with the Spitzer Space Telescope. The appearance of such boxy Fe profiles likely requires a small but non-zero magnetic field in the ejecta, which may also help to explain the appearance of apparent axisymmetric emission from Ar lines in the mid-IR spectrum of SN 2005df. Near and Mid-IR spectra generally suggest little large-scale mixing in the ejecta, in apparent contradiction of the predictions of 3D deflagration models. This presents a problem not only for pure deflagrations, but also for DD models, and suggests either that a fundamental effect is missing from deflagration models, or that something other than deflagration burning is pre-expanding the white dwarf p
Elias-Rosa N, Benetti S, Cappellaro E, et al., 2006, Anomalous extinction behaviour towards the type Ia SN 2003cg, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 369, Pages: 1880-1900, ISSN: 0035-8711
Pozzo M, Meikle WPS, Rayner JT, et al., 2006, Optical and infrared observations of the Type IIPSN 2002hh from days 3 to 397, Monthly Notices of the Royal Astronomical Society, Vol: 368, Pages: 1169-1195, ISSN: 0035-8711
We present optical and infrared (IR) observations of the Type II SN 2002hh from 3 to 397 d after explosion. The optical spectroscopic (4–397 d) and photometric (3–278 d) data are complemented by spectroscopic (137–381 d) and photometric (137–314 d) data acquired at IR wavelengths. This is the first time L-band spectra have ever been successfully obtained for a supernova (SN) at a distance beyond the Local Group. The VRI light curves in the first 40 d reveal SN 2002hh to be an SN IIP (plateau) – the most common of all core-collapse SNe. SN 2002hh is one of the most highly extinguished SNe ever investigated. To provide a match between its early-time spectrum and a coeval spectrum of the Type IIP SN 1999em, as well as maintaining consistency with K I interstellar absorption, we invoke a two-component extinction model. One component is due to the combined effect of the interstellar medium (ISM) of our Milky Way Galaxy and the SN host galaxy, while the other component is due to a ‘dust pocket’ where the grains have a mean size smaller than in the ISM. The early-time optical light curves of SNe 1999em and 2002hh are generally well matched, as are the radioactive tails of these two SNe and SN 1987A. The late-time similarity of the SN 2002hh optical light curves to those of SN 1987A, together with measurements of the optical/IR luminosity and [Fe II] 1.257 μm emission indicate that 0.07 ± 0.02 M⊙ of 56Ni was ejected by SN 2002hh. However, during the nebular phase the HKL′ luminosities of SN 2002hh exhibit a growing excess with respect to those of SN 1987A. We attribute much of this excess to an IR-echo from a pre-existing, dusty circumstellar medium. Based on an IR-echo interpretation of the near-IR (NIR) excess, we deduce that the progenitor of SN 2002hh underwent recent mass-loss of ∼0.3 M⊙. A detailed comparison of the late-time optical and NIR spectra of SNe 1987A and 2002hh is presented. While the overall im
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