Open AccessThe X‐ray emission from Nova V382 Velorum – I. The hard component observed with BeppoSAX
Author(s) -
Orio M.,
Parmar A.,
Benjamin R.,
Amati L.,
Frontera F.,
Greiner J.,
Ögelman H.,
Mineo T.,
Starrfield S.,
Trussoni E.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04448.x
Subject(s) - physics , astrophysics , ejecta , flux (metallurgy) , nova (rocket) , plasma , astronomy , x ray , supernova , optics , materials science , aeronautics , quantum mechanics , engineering , metallurgy
We present BeppoSAX observations of Nova Velorum 1999 (V382 Vel), carried out in a broad X‐ray band covering 0.1–300 keV only 15 d after the discovery and again after 6 months. The nova was detected at day 15 with the BeppoSAX instruments which measured a flux F x ≃1.8×10 −11 erg cm −2 s −1 in the 0.1–10 keV range and a 2 σ upper limit F x <6.7×10 −12 erg cm −2 s −1 in the 15–60 keV range. We attribute the emission to shocked nebular ejecta at a plasma temperature kT≃6 keV . At six months no bright component emerged in the 15–60 keV range, but a bright central supersoft X‐ray source appeared. The hot nebular component previously detected had cooled to a plasma temperature kT<1 keV . There was strong intrinsic absorption of the ejecta in the first observation and not in the second, because the column density of neutral hydrogen decreased from N(H)≃1.7×10 23 to N(H)≃10 21 cm −2 (close to the interstellar value). The unabsorbed X‐ray flux also decreased from F x =4.3×10 −11 to F x ≃10 −12 erg cm −2 s −1 .