Host galaxy subtraction of TeV candidate BL Lacertae objects

TL;DR

This paper provides correction tables for host galaxy fluxes of 20 TeV candidate BL Lac objects, highlighting the dependence on aperture radius and minimal effect of FWHM, aiding optical monitoring accuracy.

Contribution

It introduces a method to derive and tabulate host galaxy flux corrections considering aperture radius and FWHM for BL Lac objects.

Findings

Fluxes depend strongly on aperture radius.

FWHM has minor effect on flux measurements.

Constructed new calibration star sequences for 9 objects.

Abstract

We have derived R-band host galaxy fluxes of 20 TeV candidate BL Lacertae objects as a function of aperture radius and FWHM. The results are given as correction tables, that list the fluxes (in mJy) of all ``contaminating'' sources (host galaxy + significant nearby objects) as a function of aperture radius and FWHM. We found that the derived fluxes depend strongly on aperture radius, but the FWHM has only a minor effect (a few percent). We also discuss the implications of our findings to optical monitoring programs and potential sources of error in our derived fluxes. During this work we have also constructed new calibration star sequences for 9 objects and present the finding charts and calibrated magnitudes.