VLT spectropolarimetry of the optical transient in NGC 300

Patat, F.; Maund, Justyn R.; Benetti, S.; Botticella, M. T.; Harutyunyan, A.; Turatto, M.

doi:10.1051/0004-6361/200913083

Cited by 32 publications

(39 citation statements)

References 60 publications

(106 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We note that the ISP wavelength dependence observed in several supernovae, not only of Type Ia, clearly deviates from the Galactic Serkowski law (Leonard & Filippenko 2001;Maund et al 2007Maund et al , 2010Patat et al 2010). Notably, the Type II SN 1991gi shows a normal wavelength dependence (K = 1.15 and λ max = 0.51 μm, Leonard et al 2002).…”

Section: Selection Effectsmentioning

confidence: 71%

Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae

Patat

Taubenberger

Cox

et al. 2015

A&A

Self Cite

136

View full text Add to dashboard Cite

Aims. The aim of this paper is twofold: 1) to investigate the properties of extragalactic dust and compare them to what is seen in the Galaxy; 2) to address in an independent way the problem of the anomalous extinction curves reported for reddened Type Ia Supernovae (SN) in connection to the environments in which they explode. Methods. The properties of the dust are derived from the wavelength dependence of the continuum polarization observed in four reddened Type Ia SN: 1986G, 2006X, 2008fp, and 2014J. The method is based on the observed fact that Type Ia SN have a negligible intrinsic continuum polarization. This and their large luminosity makes them ideal tools to probe the dust properties in extragalactic environments.Results. All four objects are characterized by exceptionally low total-to-selective absorption ratios (R V ) and display an anomalous interstellar polarization law, characterized by very blue polarization peaks. In all cases the polarization position angle is well aligned with the local spiral structure. While SN 1986G is compatible with the most extreme cases of interstellar polarization known in the Galaxy, SN 2006X, 2008fp, and 2014J show unprecedented behaviours. The observed deviations do not appear to be connected to selection effects related to the relatively large amounts of reddening characterizing the objects in the sample. Conclusions. The dust responsible for the polarization of these four SN is most likely of interstellar nature. The polarization properties can be interpreted in terms of a significantly enhanced abundance of small grains. The anomalous behaviour is apparently associated with the properties of the galactic environment in which the SN explode, rather than with the progenitor system from which they originate. For the extreme case of SN 2014J, we cannot exclude the contribution of light scattered by local material; however, the observed polarization properties require an ad hoc geometrical dust distribution.

show abstract

Section: Selection Effectsmentioning

confidence: 71%

Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae

Patat

Taubenberger

Cox

et al. 2015

A&A

Self Cite

136

View full text Add to dashboard Cite

show abstract

“…The total EW of the D 2 line is 0.20 ± 0.02 Å, implying that E B−V = 0.03 for a MW dust/gas mixture (Munari & Zwitter 1997). Although there is mounting evidence that the Serkowski law is not universal (Leonard & Filippenko 2001;Leonard et al 2002;Maund et al 2007;Patat et al 2009Patat et al , 2010, we reckon that it is very plausible the ISP in the host galaxy is small, most likely below 0.3%. For this reason, we assume in the following that the ISP negligible.…”

Section: Reddening and Interstellar Polarizationmentioning

confidence: 80%

Asymmetries in the type IIn SN 2010jl

Patat

Taubenberger

Benetti

et al. 2011

A&A

Self Cite

View full text Add to dashboard Cite

Aims. We study possible signs of asymmetry in the luminous type IIn SN 2010jl, to obtain independent information about its explosion geometry. Methods. We performed optical linear spectropolarimetry of SN 2010jl two weeks after the discovery, in the spectral range 3700-8800 Å.Results. The object exhibits a continuum polarization at a very significant and almost constant level (1.7-2.0%). Distinctive line depolarization is seen at the positions of the strongest emission features, such as Hα and Hβ. This implies that the line forming region is well above the photosphere. The continuum polarization level (1.7-2.0%) indicates a substantial asphericity, of axial ratio ≤0.7. The almost complete depolarization seen at Hα is indicative of a very low level of interstellar polarization (≤0.3%). This rules out the presence of relevant amounts of dust in the progenitor environment at the time of our observations. From a polarimetric point of view, SN 2010jl appears to be very similar to the two other well-studied type IIn SNe 1997eg and 1998S, establishing a strong link between members of this class of objects.

show abstract

“…This has been observed, for instance, in SN 2001el , SN 2006X (Patat et al 2009a), in the bright optical transient in NGC 300 (Patat et al 2009b), and in SN 2005hk (Maund et al 2010a). When the ISP within the host galaxy and the Milky Way are comparable, as is the case for SN 2005ke, the position angle of the resulting polarization vector can differ substantially from the direction defined by the local spiral pattern.…”

Section: Reddening and Interstellar Polarizationmentioning

confidence: 86%

“…One important question to ask is what causes the overall asymmetry in these objects, as opposed to what is seen in corenormal SNe Ia explosions like SN 2006X (Patat et al 2009b, see also Fig. 8), and whether this can tell us something about the explosion mechanism that leads to these events.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

VLT Spectropolarimetry of the Type Ia SN 2005ke

Patat¹,

Hoêflich²,

Baade³

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

Aims. In this study we try to answer the question whether or not subluminous Type Ia supernovae have additional distinctive properties when examined from the point of view of the explosion geometry. Methods. We have performed optical spectropolarimetric observations of the Type Ia SN 2005ke at 3 epochs (days −8, −7, and +76). The explosion properties are derived by comparing the data to explosion and radiation transfer models. Results. The supernova shows polarimetric properties that are very similar to the only other subluminous event for which spectropolarimetry is available, i.e. SN 1999by. The data present a very marked dominant axis, which is shared by both the continuum and lines such as Si ii λ6355, suggesting that the relatively large, global asymmetry is common to the photosphere and the line-forming region. The maximum polarization degree observed in the Si ii λ6355 absorption reaches 0.39 ± 0.08%. At variance with what is seen in core-normal Type Ia, SN 2005ke displays significant continuum polarization, which grows from the blue to the red and peaks at about 7000 Å, reaching ∼0.7%. The properties of the polarization and flux spectra can be understood within the framework of a subluminous delayed-detonation (DD), or pulsating DD scenario, or white dwarf (WD) mergers. The difference in appearance with respect to core-normal SNe Ia is caused by low photospheric temperatures in combination with layers of unburned C, and more massive layers of the products of explosive C and O burning. The comparatively high level of continuum polarization is explained in terms of a significant global asymmetry (∼15%), which is well reproduced by an oblate ellipsoidal geometry within the general context of a DD explosion. Conclusions. Our results suggest that SN 2005ke arose either from a single-degenerate system in which the WD is especially rapidly rotating, close to the break-up velocity, or from a double-degenerate merger. Based on the current polarization data, we cannot distinguish between these two possibilities. Possible tests are discussed.

show abstract

VLT spectropolarimetry of the optical transient in NGC 300

Cited by 32 publications

References 60 publications

Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae

Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae

Asymmetries in the type IIn SN 2010jl

VLT Spectropolarimetry of the Type Ia SN 2005ke

Contact Info

Product

Resources

About