An Automated Chemical Exploration of NGC 6334I at 340 au Resolution

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: El-Abd, Samer J., Brogan, Crystal L., Hunter, Todd R., Lee, Kin Long Kelvin, Loomis, Ryan A., McGuire, Brett A.
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866929251000778752
author El-Abd, Samer J.
Brogan, Crystal L.
Hunter, Todd R.
Lee, Kin Long Kelvin
Loomis, Ryan A.
McGuire, Brett A.
author_facet El-Abd, Samer J.
Brogan, Crystal L.
Hunter, Todd R.
Lee, Kin Long Kelvin
Loomis, Ryan A.
McGuire, Brett A.
contents Much of the information gleaned from observations of star-forming regions comes from the analysis of their molecular emission spectra, particularly in the radio regime. The time-consuming nature of fitting synthetic spectra to observations interactively for such line-rich sources, however, often results in such analysis being limited to data extracted from a single-dish observation or a handful of pixels from an interferometric observation. Yet, star-forming regions display a wide variety of physical conditions that are difficult, if not impossible, to accurately characterize with such a limited number of spectra. We have developed an automated fitting routine that visits every pixel in the field of view of an ALMA data cube and determines the best-fit physical parameters, including excitation temperature and column densities, for a given list of molecules. In this proof-of-concept work, we provide an overview of the fitting routine and apply it to 0".26, 1.1 km s$^{-1}$ resolution ALMA observations of two sites of massive star-formation in NGC 6334I. Parameters were found for 21 distinct molecules by generating synthetic spectra across 7.48 GHz of spectral bandwidth between 280 and 351 GHz. Spatial images of the derived parameters for each of the > 8000 pixels are presented with special attention paid to the C$_2$H$_4$O$_2$ isomers and their relative variations. We highlight the greater scientific utility of the column density and velocity images of individual molecules compared to traditional moment maps of single transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2402_13913
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An Automated Chemical Exploration of NGC 6334I at 340 au Resolution
El-Abd, Samer J.
Brogan, Crystal L.
Hunter, Todd R.
Lee, Kin Long Kelvin
Loomis, Ryan A.
McGuire, Brett A.
Astrophysics of Galaxies
Much of the information gleaned from observations of star-forming regions comes from the analysis of their molecular emission spectra, particularly in the radio regime. The time-consuming nature of fitting synthetic spectra to observations interactively for such line-rich sources, however, often results in such analysis being limited to data extracted from a single-dish observation or a handful of pixels from an interferometric observation. Yet, star-forming regions display a wide variety of physical conditions that are difficult, if not impossible, to accurately characterize with such a limited number of spectra. We have developed an automated fitting routine that visits every pixel in the field of view of an ALMA data cube and determines the best-fit physical parameters, including excitation temperature and column densities, for a given list of molecules. In this proof-of-concept work, we provide an overview of the fitting routine and apply it to 0".26, 1.1 km s$^{-1}$ resolution ALMA observations of two sites of massive star-formation in NGC 6334I. Parameters were found for 21 distinct molecules by generating synthetic spectra across 7.48 GHz of spectral bandwidth between 280 and 351 GHz. Spatial images of the derived parameters for each of the > 8000 pixels are presented with special attention paid to the C$_2$H$_4$O$_2$ isomers and their relative variations. We highlight the greater scientific utility of the column density and velocity images of individual molecules compared to traditional moment maps of single transitions.
title An Automated Chemical Exploration of NGC 6334I at 340 au Resolution
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2402.13913