Instrumental Broadening Of The SPOL Spectropolarimeter At The University Of Arizona

TL;DR

This paper estimates the instrumental broadening profiles of the SPOL spectropolarimeter at the University of Arizona for various slit widths, highlighting the importance of correcting for instrumental effects in spectroscopic observations.

Contribution

It provides the first estimation of instrumental broadening profiles for multiple slit widths of the SPOL spectropolarimeter, enabling more accurate spectroscopic measurements.

Findings

Instrumental broadening varies significantly across slit widths.

Broadening is directly proportional to slit width.

Correction for instrumental broadening is essential for accurate data.

Abstract

The Ground-based Observational Support of the Fermi Gamma-ray Space Telescope is conducted by the University of Arizona using the 2.3m Bok and 1.54m Kuiper telescopes operated by the Steward Observatory (SO). This program monitors blazar sources with spectroscopic (among others) observations. Yet, the instrumental broadenings for the different slit widths used in the spectra, are unavailable (the widths range from 2.0 to 12.7 arcsec). Using quasi-simultaneous spectroscopic observations of the blazar 3C 273 between the SO, Observatorio Astrof\'isico Guillermo Haro (OAGH), and Observatorio Astron\'omico Nacional San Pedro M\'artir (OAN-SPM), we can provide an estimation of the instrumental profile for two of the slit widths. Since the instrumental broadening and the slit width are directly proportional, we were able to estimate the instrumental broadening for all six slit widths used at the SO. We found significant variations between the instrumental profiles, emphasizing the need to correct the instrumental broadening for each aperture.