The 3D shape of Type IIb SN 2011hs

Author(s): Stevance, HF; Maund, JR; Baade, D; Bruten, J; Cikota, A; Hoflich, P; Wang, L; Wheeler, JC; Clocchiatti, A; Spyromilio, J; Patat, F; Yang, Y; Crowther, P | Abstract: We observed seven epochs of spectropolarimetry in optical wavelengths for the Type IIb SN 2011hs, ranging from-3 to +40 d with respect to V-band maximum. A high degree of interstellar polarization was detected (up to ∼3 per cent), with a peak lying blueward of 4500 A. Similar behaviours have been seen in some Type Ia supernovae (SNe), but had never been observed in a Type IIb. We find that it is most likely the result of a relative enhancement of small silicate grains in the vicinity of the SN. Significant intrinsic continuum polarization was recovered at-3 and +2 d (p = 0.55 ± 0.12 per cent and 0.75 ± 0.11 per cent, respectively). We discuss the change of the polarization angle across spectral lines and in the continuum as diagnostics for the 3D structure of the ejecta. We see a gradual rotation by about-50° in the continuum polarization angle between-2 and +18 d after V-band maximum. A similar rotation in He i λ5876, Hα and the Ca ii infrared triplet seems to indicate a strong influence of the global geometry on the line polarization features. The differences in the evolution of their respective loops on the Stokes q-u plane suggest that line specific geometries are also being probed. Possible interpretations are discussed and placed in the context of literature. We find that the spectropolarimetry of SN 2011hs is most similar to that of SN 2011dh, albeit with notable differences.

[1]  L. Tram,et al.  Rotational disruption of dust grains by radiative torques in strong radiation fields , 2018, Nature Astronomy.

[2]  L. Szabados,et al.  Gaia Data Release 2 , 2018, Astronomy & Astrophysics.

[3]  J. Maund,et al.  Probing the rotational velocity of Galactic WO stars with spectropolarimetry , 2018, Monthly Notices of the Royal Astronomical Society.

[4]  Jake Vanderplas,et al.  The Astropy Project: Building an inclusive, open-science project and status of the v2.0 software , 2018 .

[5]  Miguel de Val-Borro,et al.  The Astropy Project: Building an Open-science Project and Status of the v2.0 Core Package , 2018, The Astronomical Journal.

[6]  S. P. Littlefair,et al.  THE ASTROPY PROJECT: BUILDING AN INCLUSIVE, OPEN-SCIENCE PROJECT AND STATUS OF THE V2.0 CORE PACKAGE , 2018 .

[7]  J. Spyromilio,et al.  Common continuum polarization properties: a possible link between proto-planetary nebulae and Type Ia Supernova progenitors , 2017, 1707.02300.

[8]  J. Maund,et al.  The evolution of the 3D shape of the broad-lined Type Ic SN 2014ad , 2017, 1704.06270.

[9]  P. Mazzali,et al.  Three-dimensional Explosion Geometry of Stripped-envelope Core-collapse Supernovae. II. Modeling of Polarization , 2017, 1702.03127.

[10]  Thiem C. Hoang Properties and Alignment of Interstellar Dust Grains toward Type Ia Supernovae with Anomalous Polarization Curves , 2015, The Astrophysical Journal.

[11]  J. Maund,et al.  Spectropolarimetry of the Type IIb SN 2008aq , 2016, 1606.05465.

[12]  J. Maund,et al.  Spectropolarimetry of the Type Ib Supernova iPTF 13bvn: revealing the complex explosion geometry of a stripped-envelope core-collapse supernova , 2015, 1510.02492.

[13]  Paul S. Smith,et al.  Spectropolarimetry of SN 2011dh in M51: geometric insights on a Type IIb supernova progenitor and explosion , 2015, 1506.08844.

[14]  D. Baade,et al.  Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae , 2014, 1407.0136.

[15]  P. Chandra,et al.  UNCOVERING THE PUTATIVE B-STAR BINARY COMPANION OF THE SN 1993J PROGENITOR , 2014, 1405.4863.

[16]  M. Phillips,et al.  SN 2011hs: a fast and faint Type IIb supernova from a supergiant progenitor , 2014, 1401.2368.

[17]  Copenhagen,et al.  The death of massive stars – I. Observational constraints on the progenitors of Type II-P supernovae , 2008, 0809.0403.

[18]  E. Müller,et al.  Three-dimensional neutrino-driven supernovae: neutron star kicks, spins, and asymmetric ejection of nucleosynthesis products , 2012, 1210.8148.

[19]  A. Burrows Colloquium: Perspectives on core-collapse supernova theory , 2012, 1210.4921.

[20]  J. Greenberg,et al.  Interstellar Dust and Related Topics , 2012 .

[21]  J. Prochaska,et al.  An empirical relation between sodium absorption and dust extinction , 2012, 1206.6107.

[22]  H. Janka Explosion Mechanisms of Core-Collapse Supernovae , 2012, 1206.2503.

[23]  Chien Y. Peng,et al.  THE CARNEGIE-IRVINE GALAXY SURVEY. I. OVERVIEW AND ATLAS OF OPTICAL IMAGES , 2011, 1111.4605.

[24]  S. Woosley,et al.  Core-collapse explosions of Wolf–Rayet stars and the connection to Type IIb/Ib/Ic supernovae , 2011, 1102.5160.

[25]  Ryan Chornock,et al.  Observed Fractions of Core-Collapse Supernova Types and Initial Masses of their Single and Binary Progenitor Stars , 2010, 1006.3899.

[26]  D. Finkbeiner,et al.  Measuring Reddening with SDSS Stellar Spectra , 2011 .

[27]  Douglas P. Finkbeiner,et al.  MEASURING REDDENING WITH SLOAN DIGITAL SKY SURVEY STELLAR SPECTRA AND RECALIBRATING SFD , 2010, 1012.4804.

[28]  J. Maund,et al.  A SPECTROPOLARIMETRIC VIEW ON THE NATURE OF THE PECULIAR TYPE I SN 2005hk , 2010, 1008.3985.

[29]  R. Foley,et al.  THE TRANSITIONAL STRIPPED-ENVELOPE SN 2008ax: SPECTRAL EVOLUTION AND EVIDENCE FOR LARGE ASPHERICITY , 2010, 1001.2775.

[30]  J. Maund,et al.  THE EARLY ASYMMETRIES OF SUPERNOVA 2008D/XRF 080109 , 2009, 0908.2841.

[31]  Stephen J. Smartt,et al.  Progenitors of Core-Collapse Supernovae , 2009, 0908.0700.

[32]  R. Foley,et al.  Optical Spectroscopy of the Somewhat Peculiar Type IIb Supernova 2001ig , 2009, 0903.4179.

[33]  Lifan Wang,et al.  Spectropolarimetry of Supernovae , 2008, 0811.1054.

[34]  J. Maund Optical Spectropolarimetry With Incomplete Data Sets , 2008 .

[35]  Austin,et al.  Optical spectropolarimetry with incomplete data sets , 2008, 0802.4420.

[36]  J. Maund,et al.  Spectropolarimetry of the Type IIb Supernova 2001ig , 2007, 0709.1487.

[37]  J. Maund,et al.  Spectropolarimetry of the Type Ib/c SN 2005bf , 2007, 0707.2237.

[38]  John D. Hunter,et al.  Matplotlib: A 2D Graphics Environment , 2007, Computing in Science & Engineering.

[39]  D. Fox,et al.  A non-spherical core in the explosion of supernova SN 2004dj , 2006, Nature.

[40]  et al,et al.  The 1000 Brightest HIPASS Galaxies: H I Properties , 2004, astro-ph/0404436.

[41]  S. Smartt,et al.  The massive binary companion star to the progenitor of supernova 1993J , 2004, Nature.

[42]  D. Kasen,et al.  Analysis of the Flux and Polarization Spectra of the Type Ia Supernova SN 2001el: Exploring the Geometry of the High-Velocity Ejecta , 2003, astro-ph/0301312.

[43]  C. Tropea,et al.  Light Scattering from Small Particles , 2003 .

[44]  D. Howell,et al.  Bipolar Supernova Explosions , 2001 .

[45]  Eric Jones,et al.  SciPy: Open Source Scientific Tools for Python , 2001 .

[46]  C. Heiles 9286 Stars: An Agglomeration of Stellar Polarization Catalogs , 1999, astro-ph/9910303.

[47]  Geoffrey C. Clayton,et al.  Ultraviolet Interstellar Linear Polarization. V. Analysis of the Final Data Set , 1999 .

[48]  L. Wang,et al.  Aspherical Explosion Models for SN 1998bw/GRB 980425 , 1998, astro-ph/9808086.

[49]  Alexei V. Filippenko,et al.  Optical spectra of supernovae , 1997 .

[50]  Berkeley,et al.  PROBING THE GEOMETRY AND CIRCUMSTELLAR ENVIRONMENT OF SN 1993J IN M81 , 1997, astro-ph/9703134.

[51]  J. J. Johnson,et al.  Ultraviolet Interstellar Polarization of Galactic Starlight.I.Observations by the Wisconsin Ultraviolet Photo Polarimeter Experiment , 1996 .

[52]  Lifan Wang,et al.  Polarization of SN 1987A Revisited , 1996, astro-ph/9602156.

[53]  Molefe Mokoene,et al.  The Messenger , 1995, Outrageous Fortune.

[54]  P. Hoeflich Remarks on the Polarization Observed in SN 1993J , 1995 .

[55]  J. Wheeler,et al.  Spectropolarimetry of SN 1993J in NGC 3031 , 1993 .

[56]  M. McCall,et al.  Are supernovae round? I – The case for spectropolarimetry , 1984 .

[57]  P. Shapiro,et al.  The polarization of supernova light - A measure of deviation from spherical symmetry , 1981 .

[58]  Jeremy Bailey,et al.  Systematic variations in the wavelength dependence of interstellar linear polarization , 1976 .

[59]  D. S. Mathewson,et al.  Wavelength dependence of interstellar polarization and ratio of total to selective extinction. , 1975 .

[60]  H. V. Hulst Light Scattering by Small Particles , 1957 .

[61]  S. Chandrasekhar On the radiative equilibrium of a stellar atmosphere. X. , 1946 .