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Home -> Astronomy News -> Supernovae -> PSN J09554214+6940260
Post Info TOPIC: PSN J09554214+6940260
Blobrana


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Supernova 2014J
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Title: Interstellar-Medium Mapping in M82 through Light Echoes around Supernova 2014J
Author: Yi Yang (1), Lifan Wang (1 and 2), Dietrich Baade (3), Peter J. Brown (1), Misty Cracraft (4), Peter A. Hoflich (5), Justyn Maund (6), Ferdinando Patat (3), William B. Sparks (4), Jason Spyromilio (3), Heloise F. Stevance (6), Xiaofeng Wang (7), J. Craig Wheeler (8) ((1) Texas A&M University, (2) PMO, (3) ESO, (4) STScI, (5) Florida State University, (6) University of Sheffield, (7) Tsinghua University, (8) University of Texas at Austin)

We present multiple-epoch measurements of the size and surface brightness of the light echoes from supernova (SN) 2014J in the nearby starburst galaxy M82. Hubble Space Telescope (HST) ACS/WFC images were taken ~277 and ~416 days after B-band maximum in the filters F475W, F606W, and F775W. Observations with HST WFC3/UVIS images at epochs ~216 and ~365 days (Crotts_2015) are included for a more complete analysis. The images reveal the temporal evolution of at least two major light-echo components. The first one exhibits a filled ring structure with position-angle-dependent intensity. This radially-extended, diffuse echo indicates the presence of an inhomogeneous interstellar dust cloud ranging from ~100 pc to ~500 pc in the foreground of the SN. The second echo component appears as an unresolved luminous quarter-circle arc centred on the SN. The wavelength dependence of scattering measured in different dust components suggests that the dust producing the luminous arc favours smaller grain sizes, while that causing the diffuse light echo may have sizes similar to those of the Milky Way-like dust. Smaller grains can produce an optical depth consistent with that along the supernova-Earth line of sight measured by previous studies around maximum light. Therefore, it is possible that the dust slab, from which the luminous arc arises, is also responsible for most of the extinction towards the SN 2014J. The optical depths produced by the diffuse Milky Way-like dust in the scattering matters are lower than that produced by the dust slab.

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Blobrana


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Title: Supernova 2014J at M82: II. Direct Analysis of Spectra Obtained with Isaac Newton and William Herschel Telescopes
Author: Patrick Vallely, M.E. Moreno-Raya, E. Baron, Pilar Ruiz-Lapuente, I. Dominguez, Lluis Galbany, J. I. Gonzalez Hernandez, J. Mendez, M. Hamuy, A. R. Lopez-Sanchez, S. Catalan, E. Cooke, C. Farina, R. Genova-Santos, R. Karjalainen, H. Lietzen, J. McCormac, F. Riddick, J. A. Rubino-Martin, I. Skillen V. Tudor, O. Vaduvescu

We analyze a time series of optical spectra of SN 2014J from almost two weeks prior to maximum to nearly four months after maximum. We perform our analysis using the SYNOW code, which is well suited to track the distribution of the ions with velocity in the ejecta. We show that almost all of the spectral features during the entire epoch can be identified with permitted transitions of the common ions found in normal SNe Ia in agreement with previous studies.
We show that 2014J is a relatively normal SN Ia. At early times the spectral features are dominated by Si II, S II, Mg II, and Ca II. These ions persist to maximum light with the appearance of Na I and Mg I. At later times iron-group elements also appear, as expected in the stratified abundance model of the formation of normal type Ia SNe.
We do not find significant spectroscopic evidence for oxygen, until 100 days after maximum light, which also indicates that there is not significant mixing of Ni56 to higher velocities. The +100 day identification of oxygen is tentative, and would imply significant mixing of unburned or only slight processed elements down to a velocity of 6,000 km/s. Our results are in relatively good agreement with other analyses in the IR. We briefly compare SN 2011fe to SN 2014J and conclude that the differences could be due to different central densities at ignition or differences in the C/O ratio of the progenitors.

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Blobrana


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Title: Gamma-rays from Type Ia supernova SN2014J
Author: E.Churazov, R.Sunyaev, J.Isern, I.Bikmaev, E.Bravo, N.Chugai, S.Grebenev, P.Jean, J.Knödlseder, F.Lebrun, E.Kuulkers

The whole set of INTEGRAL observations of type Ia supernova SN2014J, covering the period 16-162 days after the explosion has being analysed. For spectral fitting the data are split into early and late periods covering days 16-35 and 50-162, respectively, optimised for Ni-56 and Co-56 lines. As expected for the early period much of the gamma-ray signal is confined to energies below ~200 keV, while for the late period it is most strong above 400 keV. In particular, in the late period Co-56 lines at 847 and 1248 keV are detected at 4.7 and 4.3 sigma respectively. The lightcurves in several representative energy bands are calculated for the entire period. The resulting spectra and lightcurves are compared with a subset of models. We confirm our previous finding that the gamma-ray data are broadly consistent with the expectations for canonical 1D models, such as delayed detonation or deflagration models for a near-Chandrasekhar mass WD. Late optical spectra (day 136 after the explosion) show rather symmetric Co and Fe lines profiles, suggesting that unless the viewing angle is special, the distribution of radioactive elements is symmetric in the ejecta.

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Blobrana


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SN 2014J
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Title: Observations of the M82 SN 2014J with the Kilodegree Extremely Little Telescope
Author: Robert J. Siverd (1), Ariel Goobar (2), Keivan G. Stassun (1,3), Joshua Pepper (4,1), ((1) Vanderbilt University, (2) Stockholm University, (3) Fisk University, (4) Lehigh University)

We report observations of the bright M82 supernova 2014J serendipitously obtained with the Kilodegree Extremely Little Telescope (KELT). The SN was observed at high cadence for over 100 days, from pre-explosion, to early rise and peak times, through the secondary bump. The high cadence KELT data with high S/N is completely unique for SN 2014J and for any other SNIa, with the exception of the (yet) unpublished Kepler data. Here, we report determinations of the SN explosion time and peak time. We also report measures of the "smoothness" of the light curve on timescales of minutes/hours never before probed, and we use this to place limits on energy produced from short-lived isotopes or inhomogeneities in the explosion or the circumstellar medium. From the non-observation of significant perturbations of the light curves, we derive a 3sigma upper-limit corresponding to 8.7 x 10^36 erg/s for any such extra sources of luminosity at optical wavelengths.

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Blobrana


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Supernova 2014J
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Title: The puzzling early detection of low velocity 56Ni decay lines in SN 2014J: Hints of a compact remnant
Author: Rachid Ouyed (1), Denis Leahy (1), Nico Koning (1), Jan E. Staff (2) ((1) Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada, (2) Department of Physics and Astronomy, Macquarie University, Australia)

We show that the low-velocity 56Ni decay lines detected earlier than expected in the type Ia SN 2014J find an explanation in the Quark-Nova Ia model which involves the thermonuclear explosion of a tidally disrupted sub-Chandrasekhar White Dwarf in a tight Neutron-Star-White-Dwarf binary system. The explosion is triggered by impact from the Quark-Nova ejecta on the WD material; the Quark-Nova is the explosive transition of the Neutron star to a Quark star triggered by accretion from a CO torus (the circularized WD material). The presence of a compact remnant (the Quark Star) provides: (i) an additional energy source (spin-down power) which allows us to fit the observed light-curve including the steep early rise; (ii) a central gravitational potential which slows down some of the 56Ni produced to velocities of a few 1000 km/s. In our model, the 56Ni decay lines become optically visible at ~20 days from explosion time in agreement with observations. We list predictions that can provide important tests for our model.

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Blobrana


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Title: Light Echoes From Supernova 2014J in M82
Author: Arlin Crotts

Type Ia SN 2014J exploded in the nearby starburst galaxy M82 = NGC 3032, and was discovered at Earth about seven days later on 2014 January 21, reaching maximum light around 2014 February 5. SN 2014J is the closest SN Ia in at least four decades and probably many more. Recent HST/WFC3 imaging (2014 September 5) of M82 in the vicinity of SN 2014J reveals what is most probably a light echo at radii of about 0.55 arcsec from SN 2014J (corresponding to about 11 pc at the distance of M82). Possibly additional light echoes also reside at smaller radii of about 0.3 arcsec. The major echo signal corresponds to echoing material about 300 pc in the foreground of SN 2014J, and are bright where pre-existing nebular structure in M82 is also bright. This last pattern suggests that dark lanes throughout M82 might be represented better by the absence of reflecting material rather than obscuring dust lanes, which in this case should have produced strong echo signals but did not. Observations of echoes from SN 2014J over the next few years should allow us to map and explore further dark and light structures in M82, and further refine this conclusion, and the three-dimensional structure of gas and dust. Echoes in the near future might also reveal circumstellar structure around SN 2014J's progenitor star.

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INTEGRAL catches dead star exploding in a blaze of glory

Astronomers using ESA's Integral gamma-ray observatory have demonstrated beyond doubt that dead stars known as white dwarfs can reignite and explode as supernovae. The finding came after the unique signature of gamma rays from the radioactive elements created in one of these explosions was captured for the first time.
The explosions in question are known as Type Ia supernovae, long suspected to be the result of a white dwarf star blowing up because of a disruptive interaction with a companion star. However, astronomers have lacked definitive evidence that a white dwarf was involved until now. The 'smoking gun' in this case was evidence for radioactive nuclei being created by fusion during the thermonuclear explosion of the white dwarf star.
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Blobrana


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Posts: 131433
Date:
SN 2014J
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M82 SN2014J: NASA's Chandra Observatory Searches for Trigger of Nearby Supernova

New data from NASA's Chandra X-ray Observatory has provided stringent constraints on the environment around one of the closest supernovas discovered in decades. The Chandra results provide insight into possible cause of the explosion, as described in our press release.
On January 21, 2014, astronomers witnessed a supernova soon after it exploded in the Messier 82, or M82, galaxy.
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Blobrana


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RE: PSN J09554214+6940260
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Title: Swift Ultraviolet Observations of Supernova 2014J in M82: Large Extinction from Interstellar Dust
Author: Peter J. Brown, Michael T. Smitka, Lifan Wang, Alice Breeveld, Massimiliano de Pasquale, Dieter H. Hartmann, Kevin Krisciunas, N. P. M. Kuin, Peter A. Milne, Mat Page, Michael Siegel

We present optical and ultraviolet (UV) photometry and spectra of the very nearby and highly reddened supernova (SN) 2014J in M82 obtained with the Swift Ultra-Violet/Optical Telescope (UVOT). Comparison of the UVOT grism spectra of SN~2014J with Hubble Space Telescope observations of SN2011fe or UVOT grism spectra of SN~2012fr are consistent with an extinction law with a low value of R_V~1.4. The high reddening causes the detected photon distribution in the broadband UV filters to have a much longer effective wavelength than for an unreddened SN. The light curve evolution is consistent with this shift and does not show a flattening due to photons being scattered back into the line of sight. The light curve shapes and color evolution are inconsistent with a contribution scattered into the line of sight by circumstellar dust. We conclude that most or all of the high reddening must come from interstellar dust. We show that even for a single dust composition, there is not a unique reddening law caused by circumstellar scattering. Rather, when considering scattering from a time-variable source, we confirm earlier studies that the reddening law is a function of the dust geometry, column density, and epoch. We also show how an assumed geometry of dust as a foreground sheet in mixed stellar/dust systems will lead to a higher inferred R_V. Rather than assuming the dust around SNe is peculiar, SNe may be useful probes of the interstellar reddening laws in other galaxies.

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Blobrana


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Posts: 131433
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Supernova 2014J
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Title: First detection of 56Co gamma-ray lines from type Ia supernova (SN2014J) with INTEGRAL
Author: E.Churazov, R.Sunyaev, J.Isern, J.Knödlseder, P.Jean, F.Lebrun, N.Chugai, S.Grebenev, E.Bravo, S.Sazonov, M.Renaud

We report the first ever detection of 56Co lines at 847 and 1237 keV and a continuum in the 200-400 keV band from the Type Ia supernova SN2014J in M82 with INTEGRAL observatory. The data were taken between 50th and 100th day since the SN2014J outburst. The line fluxes suggest that 0.62±0.13 solar masses of radioactive 56Ni were synthesized during the explosion. Line broadening gives a characteristic ejecta expansion velocityVe ~ 2100±500 km s^-1. The flux at lower energies (200-400 keV) flux is consistent with the three-photon positronium annihilation, Compton downscattering and absorption in the ~ 1.4 solar masses ejecta composed from equal fractions of iron-group and intermediate-mass elements and a kinetic energy Ek 1.4 10^51 erg. All these parameters are in broad agreement with a "canonical" model of an explosion of a Chandrasekhar-mass White Dwarf (WD), providing an unambiguous proof of the nature of Type Ia supernovae as a thermonuclear explosion of a solar mass compact object.

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