The HOTT Archive

The Planck thermal dust model (Planck Collaboration et. al. 2014) at resolution 5' was used to find the zero level adjustments for the four Herschel intensity maps for each field. A table of these adjustments is available in PDF format for preview and download, and in CSV format for download.

The SED fit using χ² minimization requires accurate uncertainties for weighting. We investigated and quantified multiple sources of uncertainty in the observed intensity maps. The uncertainties assessed fall into four main categories:

1. - Instrument noise
2. - The Cosmic Infrared Background Anisotropy, a contaminating sky signal
3. - Gradient-related noise arising because of the morphology of the dust signal
4. - Calibration uncertainty, scaling with the signal strength

Detailed explanations of each of the sources have been presented in Singh & Martin (2022).

There are various ways to convert τ maps to column density. One commonly used method to obtain the column density of H₂ requires the dust opacity κ. In various analyses using HOTT maps, the following values have been adopted:

1. - Gas to Dust ratio: 100
2. - Dust opacity at 1 THz: 10 cm² g^-1
3. - Mean molecular mass for H₂: 2.8 m_H

As emphasized in Singh & Martin (2022), the value of κ is quite uncertain, and could vary from region to region and even within an individual field.

1. - Lupus: HOTT maps for Lupus_I are compromised by abnormal artifacts appearing as parallel bands across the 160 micron image.
2. - Pipe: HOTT maps for Pipe_fill_1 are compromised by a prominent grid pattern in the 160 micron image. Additionally, we caution against using Pipe_fill_2 and Pipe_fill_3 as the χ² distribution from the MBB fits is quite different from the theoretical expectation.
3. - Polaris: We did not generate HOTT maps for this region because the high level intensity images available on the Herschel Science Archive were mosaics from multiple pointings (AORs). Our pipeline works on images from cross-scanned data from a single AOR.

During the course of the analysis in Singh & Martin (2022), we have generated HOTT maps for various fields not in the Gould Belt, including low intensity fields at intermediate Galactic latitude (Draco and Spider) and GMCs that are forming massive stars (California and W3). These HOTT maps will be added to this archive. Additionally, we anticipate adding additional fields from HOBYS.