INNOVATIONS IN THE ANALYSIS OF CHANDRA-ACIS OBSERVATIONS

By Patrick S. Broos, L. Townsley, Eric D. Feigelson, Konstantin Getman, F. E. Bauer, G. Garmire. 2010

210 citations recorded by the source corpus.

As members of the instrument team for the Advanced CCD Imaging Spectrometer (ACIS) on NASA's Chandra X-ray Observatory and as Chandra General Observers, we have developed a wide variety of data analysis methods that we believe are useful to the Chandra community, and have constructed a significant body of publicly available software (the ACIS Extract package) addressing important ACIS data and science analysis tasks. This paper seeks to describe these data analysis methods for two purposes: to document the data analysis work performed in our own science projects and to help other ACIS observers judge whether these methods may be useful in their own projects (regardless of what tools and procedures they choose to implement those methods). The ACIS data analysis recommendations we offer here address much of the workflow in a typical ACIS project, including data preparation, point source detection via both wavelet decomposition and image reconstruction, masking point sources, identification of diffuse structures, event extraction for both point and diffuse sources, merging extractions from multiple observations, nonparametric broadband photometry, analysis of low-count spectra, and automation of these tasks. Many of the innovations presented here arise from several, often interwoven, complications that are found in many Chandra projects: large numbers of point sources (hundreds to several thousand), faint point sources, misaligned multiple observations of an astronomical field, point source crowding, and scientifically relevant diffuse emission.

Subfields: Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/2cc7addec5cb9f50cd4949d977c5b84c8b871189

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In Astronomy and Astrophysics

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3. P. Hopkins
4. L. Hernquist
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In Computational Mechanics

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Citations in the corpus

• The stellar rotation–activity relationship in fully convective M dwarfs (2018, methodology): “Point source extraction was performed using the ACIS EXTRACT (AE; Broos et al. 2010) software package, which allows for positional improvement, source list refinement, spectral extraction, and the production of light curves.”
• X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue (2014, methodology): “The ACIS EXTRACT (AE) software package (Broos et al. 2010) was used to extract spectra for each source following Brightman & Ueda (2012).”
• A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys (2013, methodology): “…screened for hot pixels and cosmic afterglows as described in Laird et al. (2009), astrometric corrections made as described in Rangel et al. (2013) and the source spectra were extracted using the ACIS EXTRACT (AE) software package1 (Broos et al. 2010), using the positions of the E-CDF-S sources.”
• THE CHANDRA DEEP FIELD-SOUTH SURVEY: 4 Ms SOURCE CATALOGS (2008, methodology): “…in § 3 of L08 in the production of our source catalogs, we extensively made use of the ACIS Extract (AE; version released on 2010 February 26; Broos et al. 2010)29 point-source analysis software that appropriately computes source properties when multiple observations with different roll…”
• THE 2 Ms CHANDRA DEEP FIELD-NORTH SURVEY AND THE 250 Ks EXTENDED CHANDRA DEEP FIELD-SOUTH SURVEY: IMPROVED POINT-SOURCE CATALOGS (2016, methodology): “To implement the improved methodology, we make extensive use of the ACIS Extract (AE; Broos et al. 2010)12 point-source analysis software that accurately computes source X-ray properties (most importantly pointspread function; PSF), when combining multiple observations that have different roll…”
• THE 4 Ms CHANDRA DEEP FIELD-SOUTH NUMBER COUNTS APPORTIONED BY SOURCE CLASS: PERVASIVE ACTIVE GALACTIC NUCLEI AND THE ASCENT OF NORMAL GALAXIES (2012, methodology): “The X11 source-detection criteria make use of bothwavdetect (Freeman et al. 2002) for initial source selection andACIS Extract (AE) to improve photometry and re-evaluate source-detection significance (Broos et al. 2010).”
• OBSCURATION-DEPENDENT EVOLUTION OF ACTIVE GALACTIC NUCLEI (2015, methodology): “Extraction and analysis of X-ray spectra For the Chandra surveys, the ACIS EXTRACT (AE) software package (Broos et al. 2010) was used to extract spectra for each source.”
• COLOR–MAGNITUDE RELATIONS OF ACTIVE AND NON-ACTIVE GALAXIES IN THE CHANDRA DEEP FIELDS: HIGH-REDSHIFT CONSTRAINTS AND STELLAR-MASS SELECTION EFFECTS (2010, background): “5−8 keV,int estimates to be in good agreement with those derived from spectral fitting utilizing ACIS Extract21 (F. Bauer et al., in preparation), in terms of correlation and dispersion.”