What is the Point of Interest (POI) Broker?
The Point of Interest broker is a future LSST alert broker
and currently a prototype with ZTF.
We are ingesting alerts from the ZTF survey and processing them. We are providing information for observed astronomical objects, such as
the complete light curve, changes in light curve parameters (features), cross-matches to observations from other surveys, and an observing planning tool.
A bit more technical information:
The Point of Interest broker is a downstream broker from ANTARES.
We are ingesting that portion of alerts that is seen by ANTARES as a high-amplitude variable star (broker topic high_amplitude_variable_star_candidate_staging).
How do I lookup data in the Point of Interest broker?
You can look for the most recently observed objects from which we have received an alert. The table is automatically sorted to show the most recent
alert on top.
You can filter and sort alerts by any column provided. You can thus e.g. look up objects by their RA and Dec.
How do I cite the Point of Interest broker?
A paper will be out soon. In the meanwhile, please mention us in the acknowledgements of your paper.
What other brokers are out there?
There are several other groups developing brokers to process the ZTF alert stream.
The full list of brokers is as follows:
Rubin Observatory Full-Stream Alert Brokers
- Alerce
- AMPEL
- ANTARES
- Babamul
- Fink
- Lasair
- Pitt-Google
Rubin Observatory Downstream Alert Brokers
Descriptions of Table Values
- date: The date of the alert
- alert_id: ZTF transient candidate, unique to an alert
- ztf_object_id: ZTF identifier for this astronomical object, unique to an astronomical object, appears in all alerts for this object
- mjd: observation time at start of exposure, given in Julian date
- ant_passband: Filter name (g, R, i) derived from ZTF fid (1, 2, 3)
- ra: Right Ascension of candidate; J2000 [deg]
- dec: Declination of candidate; J2000 [deg]
- ant_mag_corrected: Magnitude from PSF-fit photometry measured from difference image, obtained from ANTARES [mag]
Available Filters
- You can filter the columns by entering values and then click the "Filter" button.
- You can enter a specific value for the columns date, candid, objectId. You can also enter ranges in fields such as "magpf", Enter one of the following:
- >18
- <18
- 18.8 19.4
- You can also filter the columns by clicking the sort indicators to sort in either ascending or descending order.
Viewing details of a single alert
Clicking on the ztf_object_id of an alert in the main table will bring you to that alert’s detail page.
Here you can see a plot of the light curve, thumbnails (cutout images), calculated features including how they change over time, an observing planning tool, a cross-match to other
surveys and classification.
Thumbnails
The three cutouts are taken from the alert and display the 1x1 arcmin area surrounding the alert.
Observing Planning Tool
The observing planning tool assists with planning folow-up observations. Users can chose from a list of observatories, or enter their own.
The moon is displayed according to the latitute of the observer.br>br>
Light Curve Features
Light curve features are derived properties of light curves.
Depending on the number of observations, some features might not be calculated (i.e.: too few observations).
Only features which can be calculated for this light curve are displayed.
As Point of Interest is a downstream broker from ANTARES, we are reusing the features calculated by ANTARES.
Differently to ANTARES which stores only the most recent set of features, calculated for the light curve with all the current alerts,
we keep a history of the features. This means, once there is a new alert for a particular object, we are adding its current set of features.
This allows to track how features change.