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Title: Time-varying sodium absorption in the Type Ia supernova 2013gh

Abstract

Context. Temporal variability of narrow absorption lines in high-resolution spectra of Type Ia supernovae (SNe Ia) is studied to search for circumstellar matter. Time series which resolve the profiles of absorption lines such as Na I D or Ca II H&K are expected to reveal variations due to photoionisation and subsequent recombination of the gases. The presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of SNe Ia and could also affect the observed reddening law. Aims. To date, there are few known cases of time-varying Na I D absorption in SNe Ia, all of which occurred during relatively late phases of the supernova (SN) evolution. Photoionisation, however, is predicted to occur during the early phases of SNe Ia, when the supernovae peak in the ultraviolet. We attempt, therefore, to observe early-time absorption-line variations by obtaining high-resolution spectra of SNe before maximum light. Methods. In this paper, we have obtained photometry and high-resolution spectroscopy of SNe Ia 2013gh and iPTF 13dge, to search for absorption-line variations. Furthermore, we study interstellar absorption features in relation to the observed photometric colours of the SNe. Results. Both SNe display deep Na I D and Ca II H&K absorptionmore » features. Furthermore, small but significant variations are detected in a feature of the Na I D profile of SN 2013gh. The variations are consistent with either geometric effects of rapidly moving or patchy gas clouds or photoionisation of Na I gas at R ≈ 10 19 cm from the explosion. Conclusions. Our analysis indicates that it is necessary to focus on early phases to detect photoionisation effects of gases in the circumstellar medium of SNe Ia. Different absorbers such as Na I and Ca II can be used to probe for matter at different distances from the SNe. Finally, the nondetection of variations during early phases makes it possible to put limits on the abundance of the species at those distances.« less

Authors:
 [1];  [1];  [1];  [2];  [2];  [3];  [4];  [5];  [4];  [6];  [1];  [7];  [7];  [1];  [8];  [9];  [10];  [1];  [11];  [12] more »; ORCiD logo [13] « less
  1. Stockholm Univ. (Sweden)
  2. Weizmann Inst. of Science, Rehovot (Israel)
  3. Carnegie Inst. of Washington, Washington, DC (United States)
  4. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  5. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Univ. of Maryland, College Park, MD (United States)
  6. Univ. of California, Berkeley, CA (United States)
  7. Univ. of California, Santa Barbara, CA (United States); Las Cumbres Observatory Global Telescope Network, Goleta, CA (United States)
  8. Univ. of Turku (Finland); Univ. of Cambridge (United Kingdom)
  9. Humboldt Univ. of Berlin (Germany)
  10. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  11. Univ. of California, Davis, CA (United States)
  12. Univ. of California, Santa Cruz, CA (United States)
  13. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Stockholm Univ. (Sweden); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC); LANL Laboratory Directed Research and Development (LDRD) Program; National Aeronautic and Space Administration (NASA); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1393067
Report Number(s):
LA-UR-17-27745
Journal ID: ISSN 0004-6361; ark:/13030/qt8v96d3ch; TRN: US1702105
Grant/Contract Number:
AC02-05CH11231; AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Astronomy and Astrophysics
Additional Journal Information:
Journal Volume: 592; Journal ID: ISSN 0004-6361
Publisher:
EDP Sciences
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; supernovae; SN 2013gh; dust; extinction; circumstellar matter; iPTF 13dge; Astronomy and Astrophysics

Citation Formats

Ferretti, Raphael, Amanullah, R., Goobar, A., Johansson, J., Vreeswijk, P. M., Butler, R. P., Cao, Y., Cenko, S. B., Doran, G., Filippenko, A. V., Freeland, E., Hosseinzadeh, G., Howell, D. A., Lundqvist, P., Mattila, S., Nordin, J., Nugent, P. E., Petrushevska, T., Valenti, S., Vogt, S., and Wozniak, Przemyslaw R. Time-varying sodium absorption in the Type Ia supernova 2013gh. United States: N. p., 2016. Web. doi:10.1051/0004-6361/201628351.
Ferretti, Raphael, Amanullah, R., Goobar, A., Johansson, J., Vreeswijk, P. M., Butler, R. P., Cao, Y., Cenko, S. B., Doran, G., Filippenko, A. V., Freeland, E., Hosseinzadeh, G., Howell, D. A., Lundqvist, P., Mattila, S., Nordin, J., Nugent, P. E., Petrushevska, T., Valenti, S., Vogt, S., & Wozniak, Przemyslaw R. Time-varying sodium absorption in the Type Ia supernova 2013gh. United States. doi:10.1051/0004-6361/201628351.
Ferretti, Raphael, Amanullah, R., Goobar, A., Johansson, J., Vreeswijk, P. M., Butler, R. P., Cao, Y., Cenko, S. B., Doran, G., Filippenko, A. V., Freeland, E., Hosseinzadeh, G., Howell, D. A., Lundqvist, P., Mattila, S., Nordin, J., Nugent, P. E., Petrushevska, T., Valenti, S., Vogt, S., and Wozniak, Przemyslaw R. 2016. "Time-varying sodium absorption in the Type Ia supernova 2013gh". United States. doi:10.1051/0004-6361/201628351. https://www.osti.gov/servlets/purl/1393067.
@article{osti_1393067,
title = {Time-varying sodium absorption in the Type Ia supernova 2013gh},
author = {Ferretti, Raphael and Amanullah, R. and Goobar, A. and Johansson, J. and Vreeswijk, P. M. and Butler, R. P. and Cao, Y. and Cenko, S. B. and Doran, G. and Filippenko, A. V. and Freeland, E. and Hosseinzadeh, G. and Howell, D. A. and Lundqvist, P. and Mattila, S. and Nordin, J. and Nugent, P. E. and Petrushevska, T. and Valenti, S. and Vogt, S. and Wozniak, Przemyslaw R.},
abstractNote = {Context. Temporal variability of narrow absorption lines in high-resolution spectra of Type Ia supernovae (SNe Ia) is studied to search for circumstellar matter. Time series which resolve the profiles of absorption lines such as Na I D or Ca II H&K are expected to reveal variations due to photoionisation and subsequent recombination of the gases. The presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of SNe Ia and could also affect the observed reddening law. Aims. To date, there are few known cases of time-varying Na I D absorption in SNe Ia, all of which occurred during relatively late phases of the supernova (SN) evolution. Photoionisation, however, is predicted to occur during the early phases of SNe Ia, when the supernovae peak in the ultraviolet. We attempt, therefore, to observe early-time absorption-line variations by obtaining high-resolution spectra of SNe before maximum light. Methods. In this paper, we have obtained photometry and high-resolution spectroscopy of SNe Ia 2013gh and iPTF 13dge, to search for absorption-line variations. Furthermore, we study interstellar absorption features in relation to the observed photometric colours of the SNe. Results. Both SNe display deep Na I D and Ca II H&K absorption features. Furthermore, small but significant variations are detected in a feature of the Na I D profile of SN 2013gh. The variations are consistent with either geometric effects of rapidly moving or patchy gas clouds or photoionisation of Na I gas at R ≈ 1019 cm from the explosion. Conclusions. Our analysis indicates that it is necessary to focus on early phases to detect photoionisation effects of gases in the circumstellar medium of SNe Ia. Different absorbers such as Na I and Ca II can be used to probe for matter at different distances from the SNe. Finally, the nondetection of variations during early phases makes it possible to put limits on the abundance of the species at those distances.},
doi = {10.1051/0004-6361/201628351},
journal = {Astronomy and Astrophysics},
number = ,
volume = 592,
place = {United States},
year = 2016,
month = 7
}

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  • We present a time series of the highest resolution spectra yet published for the nearby Type Ia supernova (SN Ia) 2014J in M82. They were obtained at 11 epochs over 33 days around peak brightness with the Levy Spectrograph (resolution R ≈ 110,000) on the 2.4 m Automated Planet Finder telescope at Lick Observatory. We identify multiple Na i D and K i absorption features as well as absorption by Ca ii H and K and several of the more common diffuse interstellar bands (DIBs). We see no evolution in any component of Na i D, Ca ii, or inmore » the DIBs, but do establish the dissipation/weakening of the two most blueshifted components of K i. We present several potential physical explanations, finding the most plausible to be photoionization of circumstellar material, and discuss the implications of our results with respect to the progenitor scenario of SN 2014J.« less
  • Recent observations have revealed that some Type Ia supernovae exhibit narrow, time-variable Na I D absorption features. The origin of the absorbing material is controversial, but it may suggest the presence of circumstellar gas in the progenitor system prior to the explosion, with significant implications for the nature of the supernova (SN) progenitors. We present the third detection of such variable absorption, based on six epochs of high-resolution spectroscopy of the Type Ia supernova SN 2007le from the Keck I Telescope and the Hobby-Eberly Telescope. The data span a time frame of approximately three months, from 5 days before maximummore » light to 90 days after maximum. We find that one component of the Na I D absorption lines strengthened significantly with time, indicating a total column density increase of {approx}2.5 x 10{sup 12} cm{sup -2}. The data limit the typical timescale for the variability to be more than 2 days but less than 10 days. The changes appear to be most prominent after maximum light rather than at earlier times when the ultraviolet flux from the SN peaks. As with SN 2006X, we detect no change in the Ca II H and K absorption lines over the same time period, rendering line-of-sight effects improbable and suggesting a circumstellar origin for the absorbing material. Unlike the previous two supernovae exhibiting variable absorption, SN 2007le is not highly reddened (E {sub B-V} = 0.27 mag), also pointing toward circumstellar rather than interstellar absorption. Photoionization calculations show that the data are consistent with a dense (10{sup 7} cm{sup -3}) cloud or clouds of gas located {approx}0.1 pc (3 x 10{sup 17} cm) from the explosion. These results broadly support the single-degenerate scenario previously proposed to explain the variable absorption, with mass loss from a nondegenerate companion star responsible for providing the circumstellar gas. We also present possible evidence for narrow H{alpha} emission associated with the SN, which will require deep imaging and spectroscopy at late times to confirm.« less
  • The Type Ia supernova (SN Ia) 2013dy in NGC 7250 (d ≈ 13.7 Mpc) was discovered by the Lick Observatory Supernova Search. Combined with a prediscovery detection by the Italian Supernova Search Project, we are able to constrain the first-light time of SN 2013dy to be only 0.10 ± 0.05 days (2.4 ± 1.2 hr) before the first detection. This makes SN 2013dy the earliest known detection of an SN Ia. We infer an upper limit on the radius of the progenitor star of R {sub 0} ≲ 0.25 R {sub ☉}, consistent with that of a white dwarf. The light curve exhibitsmore » a broken power law with exponents of 0.88 and then 1.80. A spectrum taken 1.63 days after first light reveals a C II absorption line comparable in strength to Si II. This is the strongest C II feature ever detected in a normal SN Ia, suggesting that the progenitor star had significant unburned material. The C II line in SN 2013dy weakens rapidly and is undetected in a spectrum 7 days later, indicating that C II is detectable for only a very short time in some SNe Ia. SN 2013dy reached a B-band maximum of M{sub B} = –18.72 ± 0.03 mag ∼17.7 days after first light.« less
  • On 2014 December 9.61, the All-sky Automated Survey for SuperNovae (ASAS-SN or "Assassin") discovered ASASSN-14lp just ~2 days after first light using a global array of 14 cm diameter telescopes. ASASSN-14lp went on to become a bright supernova (V = 11.94 mag), second only to SN 2014J for the year. We present prediscovery photometry (with a detection less than a day after first light) and ultraviolet through near-infrared photometric and spectroscopic data covering the rise and fall of ASASSN-14lp for more than 100 days. We find that ASASSN-14lp had a broad light curve (more » $${\rm{\Delta }}{m}_{15}(B)=0.80\pm 0.05$$), a B-band maximum at 2457015.82 ± 0.03, a rise time of $${16.94}_{-0.10}^{+0.11}$$ days, and moderate host-galaxy extinction ($$E{(B-V)}_{\mathrm{host}}=0.33\pm 0.06$$). Using ASASSN-14lp, we derive a distance modulus for NGC 4666 of $$\mu =30.8\pm 0.2$$, corresponding to a distance of 14.7 ± 1.5 Mpc. However, adding ASASSN-14lp to the calibrating sample of Type Ia supernovae still requires an independent distance to the host galaxy. Lastly, using our early-time photometric and spectroscopic observations, we rule out red giant secondaries and, assuming a favorable viewing angle and explosion time, any nondegenerate companion larger than 0.34 $${R}_{\odot }$$.« less