Gaia Photometric Science Alerts: Validation Phase

Note: The Gaia Alerts Validation Phase is now complete. New Gaia photometric alerts are being published on Gaia Photometric Science Alerts website.

Per-source alert pages, including lightcurves and BP/RP spectra are available. They can be accessed by clicking on alert names in Alerts table.

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Welcome! We have begun the experiment to validate our AlertPipe software. This software discovers, classifies and publishes Gaia Photometric Science Alerts. We are right at the beginning of the journey, and invite you to join in.

On this web page we are publishing coordinates and photometry for a manually selected subset of alerts as part of our validation process. These sources and the contents of the webpages come with a number of caveats (details below). The methodology used to find the alerts is also described below.

If you do measure any data for these targets, then please let us know (via Contact page and choose the category: Science alerts), and if possible we'd like to get a copy of your data (e.g. via ftp) for inclusion in our verification analysis together with data from collaborating observatories: http://www.ast.cam.ac.uk/ioa/wikis/gsawgwiki/index.php/Working_groups. Anything we use will be credited. Similarly, if you do publish any ATELS, articles, etc, then please do let us know.

If you publish any results based on these Gaia discoveries, we would appreciate an acknowledgement along the lines of: "We acknowledge ESA Gaia, DPAC and the Photometric Science Alerts Team (http://gaia.ac.uk/selected-gaia-science-alerts)".

(If you are looking for our "Selected targets list" published during the 2014 Royal Society Summer Science Exhibition on the old version of this page, you can still find it on Selected science alerts page.)

Jump to alert table.

Caveats

1. There may well be false alarms in here (perhaps from moving objects, spurious crossmatches, photometric errors etc).
2. The photometry is approximate (we use a single zeropoint for every measurement to convert from Gaia G-band fluxes into an approximate magnitude system). When photometric calibrations become available for Gaia, then we will start to apply them. The photometric errors have not yet been determined.
3. The coordinates currently suffer small systematics at the arcsecond level. The fix will not be applied until November at the earliest (although it is in hand).
4. We make no attempt to crossmatch our objects against discoveries in other transient surveys at this point in time - so there may well be duplication of discoveries.
5. While we will try to update this list on short (approximately weekly timescales), there may well be interruptions and stoppages in processing which can interrupt the flow of alerts, and will not obviously be notified on the pages.
6. We may stop producing these manual alerts at any time if the experiment is not working successfully, or we are preparing major code updates, or transitioning to a more automated mode of operations.
7. Individual pages per object are a feature that will be implemented in the near future. The precise content of these pages is still under discussion and development.
8. Our reliance on SDSS (see below) means that currently we are unable to produce Science Alerts for the Southern Hemisphere.
9. Gaia can observe within 45 degrees of the Sun, which is too close for ground-based telescopes. Please check observability for your observatory before attempting to observe these transients (see useful links below).

Methodology

We are producing a limited set of data for now, which will be expanded on as we proceed through the Gaia mission. While the Gaia Source catalogue is still in a state of flux, we are initially only searching for transients within a 4 arcsecond radius around SDSS (DR9) objects (both stars and galaxies). We require a delta-magnitude of >=0.5 mags (and with a significance >= 5 sigma) in the summed flux in a super-pixel (radius 4 arcseconds) compared to the historical average Gaia magnitude in the super-pixel. The alert-time in the table (UTC timestamp) is the time of measurement of the first deviating datapoint. We also require the transient event to last for at least 2 consecutive fields-of-view.

Alerts

The table can by sorted by Name, UTC timestamp, RA, Dec and AlertMag - click column heading to sort.