ScienceProblem: LowSurfaceBrightnessGalaxyDiscovery

PrimaryActor:

astronomer

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ScienceGoal:

locate large scale structures (low surface brightness galaxies (LSB's) that have low contrasts w.r.t. the background

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DataSets:

HI Parkes/Jodrell All Sky Survey: HIPASS data are already available; HIJASS is ongoing.

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ProblemDescription:

Low surface brightness systems are often missed from wide field survey catalogues due to selection effects acting against their discovery. However, it is important to locate and understand the properties of this population as they can contain significant mass (Impey & Bothun 1997).

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CurrentSolution:

Procedure is to search all objects in 2MASS for those with non-thermal colours, search near-IR source positions on the blue plates of DPOSS, and compare flux against the local sky background to find low surface brightness galaxies.

Wide area optical data can be used (e.g. WFS data - see Kambas et al, 2000).

Radio data (e.g. Arecibo HI 21cm) can also be used - radio selected LSB's are compared with optically selected sets (e.g. Zwaan et al, 2001).

The HIJASS/HIPASS all sky survey finds HI emission from candidate LSB galaxies (e.g. Banks et al. 1999); here selection rules are needed to

• distinguish the velocity profile of LSB galaxies from that of Galactic high-velocity clouds;

• search for optical counterparts in crowded regions e.g. the Galactic plane.

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VOSolution:

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Discussion:

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Iteration Breakdown:

• Astrogrid.Itn04LowSurfaceBrightnessGalaxyDiscovery - science workflow for case in Iteration 04
• Astrogrid.Itn06LowSurfaceBrightnessGalaxyDiscovery - science workflow for case in Iteration 06
• Astrogrid.Itn08LowSurfaceBrightnessGalaxyDiscovery - science workflow for case in Iteration 08

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KeyReferences:

Armandroff et al, 1998, AJ, 116

Impey & Bothun, 1997, ARA&A 35 267

Kambas et al, 2000, AJ, 120, 131

Zwaan et al, 2001, MNRAS, 327, 1249

Banks, G. D. et al., 1999, Astrophysical Journal, "New Galaxies Discovered in the First Blind H I Survey of the Centaurus A Group"

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GoodStyle: Please add comments below. This area should be used for refinement of the above document. If you want to ask questions or start a dialogue with the author, please use (or create) a topic in the Science Problems Forum. For other ScienceProblems, refer to the ScienceProblemList.
Author: Once the refinements here and comments in the forum die down, perhaps you could rewrite the problem, incorporating the comments and refinements.

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Will be an AG driver - interesting as 'poor' quality data could be used here - e.g. poor spatial resolution data. Need to run an alorithm over image data.

-- NicholasWalton - 17 Apr 2002

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Associated UseCases

See also CommonGroup of use cases

LibraryFunctions needed include: Astrometric alignment; Least squares fit; Express result as probability; Fit Gaussian components; Fit to spectra; Convert freq., velocity etc.

GalaxyMorphologyRecognition

GetFluxOrUpperLimitAtPosition

GetLiteratureReference

InstrumentFootprint

InteractiveImageInformation

LocateOutliers

-- AnitaRichards - 02 May 2002 - 07 Aug 2002

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-- NicholasWalton - 16 Apr 2002