White Dwarf Distance Estimate to M5

The A-Team: Andy Layden (PI, BGSU), Adrienne Cool (SFSU), Ted von Hippel (Gemini Observatories, Hilo), and Ata Sarajedini (Wesleyan).

Tentative Work Assignments (subject to revision):

Andy:

• Assemble and distribute HST images (recalibration, warmpix, CRrej)
• Drizzle images to obtain higher resolution, high S/N master? (with TvH).
• Ground based photometric calibration, analysis of photometric corrections (w/ TvH).
• Assemble ground based photometry of RR Lyrae from literature.
• Write RR Lyrae MV calibration paper.
• Search for variable stars (and attempt period determination) in WFPC2 and STIS data.

Adrienne:

• CRrej using local code (for her photometry, perhaps distribution).
• Photometry of WFPC2 iamges using hybrid DAOPHOT-aperture photom code.
• Assemble WFPC (and STIS?) data for ultra-deep main sequence CMD and search for mass turnover (write paper, w/ TvH?).
• Contribute to variable star effort, especially main sequence binaries.
• Assorted White Dwarf studies (write paper(s))?

Ted:

• Drizzle experiments? (w/ AL).
• Explore/apply photometric corrections (long/short corrections, etc). (w/ AL)
• Explore photometry with CCDAP, especially STIS frames?
• Compile ultra-deep main sequence photom from STIS data and model to search for mass cutoff? (write paper, w/ AC?)
• Assorted White Dwarf studies (write paper(s))?

Ata:

• Photometry of WFPC2 (and STIS?) images using DAOPHOT/ALLFRAME.
• Photometric calibration (comparison with HST WD observations?)?

Projects AL considers open -- searching for volunteers to be first author:

• Variable star search (AL has experience and programs ... could be quick once photom is finalized).
• Deep CMD to detect main sequence mass cutoff in WFPC2 a/o STIS images.

Team Meeting: Sat 14 October 2000 in Middletown, CT (directions to VVO).

Current work (topics for discussion at team meeting):

Andy:

• Matching HST photometry (currently Ata's WF2) with groundbased VI photom (Sandquist's). Possibly use ground based to calibrate HST photom. Look for non-linearities due to CTE or short/long effect.
• Look over latest STScI reports on CTE effect and short/long effect. How shall we proceede?

Adrienne:

• Photometry in WF chips using hand-chosen star lists and PSFs derived from image, with DAOPHOT/ALLSTAR. Will extend to ALLFRAME.

Ted:

• Will work with Source Extractor to determine which faint/blue objects are stellar vs non-stellar.

Ata:

• Photometry in all chips using Stetson HST PSFs with DAOPHOT/ALLFRAME.
• Work with Source Extractor to determine which which faint/blue objects are stellar vs non-stellar.

General:

• Revise "work assignments" and develop rough timeline for M_V(RR) and secondary papers.
• Discuss strategies for presenting photometry (which method(s) to use, etc) and identification of WDs (eg from galaxies and image flaws).
• How will we investigate and possibly correct for CTE and long/short effects?
• Fire everyone up!

Updated 2000 Oct 10 -- ACL