TY - JOUR
T1 - The spectroscopic evolution of the recurrent nova T Pyxidis during its 2011 outburst
T2 - III. the ultraviolet development from iron curtain through the post-X-ray turnoff
AU - De Gennaro Aquino, I.
AU - Shore, S. N.
AU - Schwarz, G. J.
AU - Mason, E.
AU - Starrfield, Sumner
AU - Sion, E. M.
N1 - Funding Information:
We thank our colleagues Jan-Uwe Ness, Bran Warner, Kim Page, Julian Osborne, Luca Izzo, Jordi José, Massimo Della Valle, Tim O’Brien, Bob Williams, and Fred Walter for vigorous, insightful, and deep exchanges, and the (anonymous) referee for a close reading and very helpful guidance. We thank Alessandro Ederoclite for discussions and correspondence regarding the ESO spectra. The HST observations were performed on GO-12200 (Schwarz, PI) and DDT-12799 and GO-12890 (Sion, PI). Support for program #12200 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. We thank the STScI director, Matt Mountain, for a generous allocation of Director’s Discretionary time to observe T Pyx in its late stages and Neil Gehrels for massive allocations of Swift observing time. SNS warmly thanks Patrick Woudt for an invitation to the University of Cape Town and Petr Harmanec for a visiting position at the Charles University (Prague) and Daniela Korcakova for many valuable discussions. S.S. acknowledges partial support form NSF and NASA grants to ASU.
PY - 2014/2
Y1 - 2014/2
N2 - We continue the analysis of the multiwavelength evolution of the recurrent nova T Pyx during its 2011 outburst, focussing on the spectral development on the 1150-3000 Å region. This extraordinary data set presents the longest temporal baseline high resolution view of the ultraviolet for any nova to date (classical or recurrent). The observations cover the early Fe-curtain stage, when the UV was completely optically thick, to 834 days after discovery when the outburst was effectively over. We present an analysis of dynamics and abundances of the interstellar species whose resonance lines are accessible in the UV. The Lyα profile is consistent with only interstellar absorption at all epochs and agrees with the H I 21 cm column density. The distance obtained to T Pyx is about 5 kpc, based on the ISM analysis. For the ejecta evolution we have been able to follow the changes in ionization and structure with previously unobtained resolution and cadence. The excited state isoelectronic transitions of C III, N IV], and O V displayed the same detached absorption lines as the optical He I transitions during the optical maximum. This is explained as resonance absorption within the ejecta of FUV ground state lines from the 300-1000 Å range. The resonance lines of all species showed absorption components between-1000 and-3000 km s-1 as soon as the Fe-curtain turned transparent (from day 105); these persisted at the same velocities and varied in strength from one ion to another through day 834. The last ultraviolet spectrum, taken more than 800 days after outburst, showed the same absorption lines on N V and C IV as day 105. There was no evidence of circumstellar absorbers. This and the related observations of profile evolution effectively rule out any wind model for the spectrum. The picture that emerges is of ejecta that became optically thin after visual maximum as the X-ray emission became visible following an outwardly propagating ionization front and for which the ionization stages froze because of ejecta expansion after the end of the soft X-ray illumination.
AB - We continue the analysis of the multiwavelength evolution of the recurrent nova T Pyx during its 2011 outburst, focussing on the spectral development on the 1150-3000 Å region. This extraordinary data set presents the longest temporal baseline high resolution view of the ultraviolet for any nova to date (classical or recurrent). The observations cover the early Fe-curtain stage, when the UV was completely optically thick, to 834 days after discovery when the outburst was effectively over. We present an analysis of dynamics and abundances of the interstellar species whose resonance lines are accessible in the UV. The Lyα profile is consistent with only interstellar absorption at all epochs and agrees with the H I 21 cm column density. The distance obtained to T Pyx is about 5 kpc, based on the ISM analysis. For the ejecta evolution we have been able to follow the changes in ionization and structure with previously unobtained resolution and cadence. The excited state isoelectronic transitions of C III, N IV], and O V displayed the same detached absorption lines as the optical He I transitions during the optical maximum. This is explained as resonance absorption within the ejecta of FUV ground state lines from the 300-1000 Å range. The resonance lines of all species showed absorption components between-1000 and-3000 km s-1 as soon as the Fe-curtain turned transparent (from day 105); these persisted at the same velocities and varied in strength from one ion to another through day 834. The last ultraviolet spectrum, taken more than 800 days after outburst, showed the same absorption lines on N V and C IV as day 105. There was no evidence of circumstellar absorbers. This and the related observations of profile evolution effectively rule out any wind model for the spectrum. The picture that emerges is of ejecta that became optically thin after visual maximum as the X-ray emission became visible following an outwardly propagating ionization front and for which the ionization stages froze because of ejecta expansion after the end of the soft X-ray illumination.
KW - Circumstellar matter
KW - Line: profiles
KW - Novae, cataclysmic variables
KW - Stars: individual: T Pyx
KW - Ultraviolet: stars
UR - http://www.scopus.com/inward/record.url?scp=84893247829&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84893247829&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201322545
DO - 10.1051/0004-6361/201322545
M3 - Article
AN - SCOPUS:84893247829
SN - 0004-6361
VL - 562
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A28
ER -