The Hubble Legacy Archive NICMOS Grism Data

TL;DR

The paper describes the calibration, data reduction, and public release of NICMOS G141 grism spectra from the Hubble Legacy Archive, facilitating access to slitless spectroscopy data for nearly 2000 targets.

Contribution

It provides detailed methods for extracting calibrated spectra from HST NICMOS slitless data and makes these data publicly accessible via VO interfaces.

Findings

2470 spectra of 1923 targets released

Spectra quality validated against IR catalogs and spectroscopy

Data accessible through web and VO interfaces

Abstract

The Hubble Legacy Archive (HLA) aims to create calibrated science data from the Hubble Space Telescope archive and make them accessible via user-friendly and Virtual Observatory (VO) compatible interfaces. It is a collaboration between the Space Telescope Science Institute (STScI), the Canadian Astronomy Data Centre (CADC) and the Space Telescope - European Coordinating Facility (ST-ECF). Data produced by the Hubble Space Telescope (HST) instruments with slitless spectroscopy modes are among the most difficult to extract and exploit. As part of the HLA project, the ST-ECF aims to provide calibrated spectra for objects observed with these HST slitless modes. In this paper, we present the HLA NICMOS G141 grism spectra. We describe in detail the calibration, data reduction and spectrum extraction methods used to produce the extracted spectra. The quality of the extracted spectra and associated direct images is demonstrated through comparison with near-IR imaging catalogues and existing near-IR spectroscopy. The output data products and their associated metadata are publicly available through a web form at http://hla.stecf.org and via VO interfaces. In total, 2470 spectra of 1923 unique targets are included in the current release.