Phase-Resolved Infrared Spectroscopy and Photometry of V1500 Cygni, and a Search for Similar Old Classical Novae

Abstract

We present phase-resolved near-infrared photometry and spectroscopy of the classical nova V1500 Cyg to explore whether cyclotron emission is present in this system. While the spectroscopy do not indicate the presence of discrete cyclotron harmonic emission, the light curves suggest that a sizable fraction of its near-infrared fluxes are due to this component. The light curves of V1500 Cyg appear to remain dominated by emission from the heated face of the secondary star in this system. We have used infrared spectroscopy and photometry to search for other potential magnetic systems amongst old classical novae. We have found that the infrared light curves of V1974 Cyg superficially resemble those of V1500 Cyg, suggesting a highly irradiated companion. The old novae V446 Her and QV Vul have light curves with large amplitude variations like those seen in polars, suggesting they might have magnetic primaries. We extract photometry for seventy nine old novae from the 2MASS Point Source Catalog and use those data to derive the mean, un-reddened infrared colors of quiescent novae. We also extract W ISE data for these objects and find that forty five of them were detected. Surprisingly, a number of these systems were detected in the W ISE 22 µm band. While two of those objects produced significant dust shells (V705 Cas and V445 Pup), the others did not. It appears that line emission from their ionized ejected shells is the most likely explanation for those detections.

The distances to Novae as seen by Gaia

“…To get to the MMRD, the peak would have to be 2.5 mag brighter than observed, and this is not plausible. The extinction value from Harrison, Campbell, & Lyke (2013) is reliable, and A V is certainly not 2.5 mag larger. Further, Liu & Hu (2000) has confidently identified the quiescent counterpart, and it is certainly the source listed in the Gaia catalog.…”

The detection of discrete cyclotron emission features in phase-resolved optical spectroscopy of V1500 Cygni

“…It would also be interesting to obtain new phase-resolved near-IR spectroscopy to search for emission from the cyclotron fundamentals. We re-examined the JHK spectra presented in Harrison et al (2013, obtained with NIRC on Keck in 2006), but could not find any evidence to support the presence of discrete cyclotron harmonic features in those data.…”

THE WISE LIGHT CURVES OF Z CAMELOPARDALIS DURING OUTBURST: EVIDENCE FOR SYNCHROTRON EMISSION?

“…The highly variable 12 μm light curve of Z Cam during an outburst suggests that, like SS Cyg, it is a synchrotron source when near visual maximum. If so, it would join the small family of synchrotron emitting CVs: SS Cyg, AE Aqr, V1223 Sgr (Harrison et al 2010), and probably EX Hya (Harrison et al 2010) and GK Per (Harrison et al 2013). There is a significant number of non-magnetic CVs in the AllWISE survey catalog that have extreme (W2 − W3) colors that suggest that they too are sources of non-thermal emission.…”

“…Harrison & Gehrz (1992) originally reported a weak IRAS 12 μm detection of Z Cam (S ν = 0.09 ± 0.03 Jy). A reexamination of the IRAS detections for classical novae using WISE imaging data (Harrison et al 2013) showed that the majority of those detections were due to source confusion. This explanation cannot be used to dismiss the detection of Z Cam, as no WISE sources this bright exist within the IRAS detection radius for this source.…”