A New Catalogue of Galactic Novae: Investigation of the MMRD relation & Spatial Distribution

TL;DR

This paper introduces a comprehensive Galactic novae catalogue, investigates the MMRD relation's scatter and dependencies, and studies the spatial distribution and nova rate in the Galaxy using new data and analysis.

Contribution

It provides a new, detailed catalogue of Galactic novae, examines the MMRD relation's scatter and potential dependencies, and estimates the Galactic nova rate and spatial distribution parameters.

Findings

MMRD relation shows significant scatter, suggesting dependence on additional parameters.

Estimated local outburst density: 3.6-4.2 × 10^{-10} pc^{-3} yr^{-1}.

Galactic nova rate estimated at approximately 67 per year.

Abstract

In this study, a new Galactic novae catalogue is introduced collecting important parameters of these sources such as their light curve parameters, classifications, full width half maximum (FWHM) of H$_\alpha$ line, distances and interstellar reddening estimates. The catalogue is also published on a website with a search option via a SQL query and an online tool to re-calculate the distance/reddening of a nova from the derived reddening-distance relations. Using the novae in the catalogue, the existence of a maximum magnitude-rate of decline (MMRD) relation in the Galaxy is investigated. Although an MMRD relation was obtained, a significant scattering in the resulting MMRD distribution still exists. We suggest that the MMRD relation likely depends on other parameters in addition to the decline time, as FWHM H$_\alpha$, the light curve shapes. Using two different samples depending on the distances in the catalogue and from the derived MMRD relation, the spatial distributions of Galactic novae as a function of their spectral and speed classes were studied. The investigation on the Galactic model parameters implies that best estimates for the local outburst density are 3.6 and 4.2 $\times 10^{-10}$ pc$^{-3}$ yr$^{-1}$ with a scale height of 148 and 175 pc, while the space density changes in the range of $0.4 - 16 \ \times 10^{-6}$ pc$^{-3}$. The local outburst density and scale height obtained in this study infer that the disk nova rate in the Galaxy is in the range of $\sim20$ to $\sim100$ yr$^{-1}$ with an average estimate $67^{+21}_{-17}$ yr$^{-1}$.