GALEX Inter-visit Alerts

We have begun implementing visit-level variable alerts at www.galex.caltech.edu/researcher/tdsalerts.html. The current version of the page for reviewing variable alert candidates can be found at nagelfar.srl.caltech.edu/vars (use dbupdt).

A database was created to ingest all the mcat files generated by the GALEX pipeline. This database allows inter-visit variability to be detected. This database can be queried at: nagelfar.srl.caltech.edu

Current status: nagelfar is adapted to ingest the new (V7) pipeline files, but ingest is awaiting the new pipeline to handle the new spatial calibration for GALEX images, required by recent changes in the NUV detector. There is a new table called vars that contains the variability index for all source positions with at least 3 NUV measurements with a S/N of 10 or greater. See nagelfar.srl.caltech.edu/vars.php for the latest variables search status.

Inter-visit Variable Alerts Plan:

Prototype:

  1. DONE: implement new variables query
  2. DONE: make web page public
  3. DONE: Produce time series data using aper4 in addition to best_mag

Longer Term:

  1. DONE: Upgrade hardware
  2. DONE: Decide how to trim database to essential data
  3. DONE: Re-build database
  4. DONE: Make new variable check part of ingest
  5. DONE: Upgrade web interface to include user queries for variables

GALEX Intra-visit Alerts

The current pipleline uses VARPIX to flag artifacts. It should be possible to add the capability to the pipeline to flag real variables above some threshhold and then pull out the photons for that object and generate a light curve. This could then be added to the variable alerts page.

Intra-visit Variable Alerts Plan:

  1. Define VARPIX threshholds for variables
  2. Determine if a separate VARPIX run is required
  3. Determine impact on pipeline
  4. Implement on development pipeline
  5. Test on known variables
  6. Quantify spurious variables
  7. Develop generation of photon-level lightcurve for variables
  8. Develop web page for alerts (integrate with inter-visit alerts)
  9. End-to-end test with development pipeline
  10. Deploy on production pipeline

GALEX Long Term and Transient Alerts

Long term variable and Transients Alerts Plan:

  1. Generate deep reference images
  2. Compare each new visit with reference
  3. Any new objects or variables not known generate alert