Home

Deep Lens Survey: Real-time Transient Detection

This page contains REAL-TIME information on detections of transient astronomical happenings from the Deep Lens Survey, on the KPNO and CTIO 4-m telescopes using the wide-field MOSAIC imagers.

A by-product of this wide-field survey is the detection of transient astronomical phenomena, including Near Earth Objects (NEO), Kupier Belt Objects (KBO), Supernova (SN), and even previously unknown events which happen with such rarity that only a deep, wide field survey, such as this one, is even reasonably sensitive to them.

The table below contains recently updated information on objects detected during the course of this survey. These are extracted from the images in real-time using a combination of SExtractor for object detection and image subtraction to provide differenced images, from which we are able to identify transient, or "new", objects, after filtering out spurious objects like cosmic rays. These objects have also been inspected by eye and categorized as probably real.

We include the date, DATE-ARCH, when the object was added to this archive or updated, the date the object was most recently observed DATE-OBS (MJD), and the FILTER of this observation. Additionally, we include the RA and DEC (J2000, to ~0.5'' accuracy) of the object, a preliminary categorization of the nature of the transient, and a preliminary estimate of the magnitude of the variability (+/- 0.1 mag in R and B, +/- 0.5 in V and z, in photometric conditions). We do not take into account extinction due to non-photometric conditions. Two types of images are available for download: .jpg mosaics and .fits finding charts.

The mosaic page includes a time-series of JPEGs showing 200-pixel (50") postage stamps, with time increasing from top to bottom. The discovery mosic includes a template observation on the left, discovery image in the middle, and difference image on the right. Subsequent mosaics show a similar collection of images, or the new observation image only, in the case where a subtraction image was not available. The files are generally a few hundred kilobytes. In CTIO mosaics, East is up and North is to the right. For KPNO, East is down and North is to the left.

The finding charts are 3'x3' FITS images centered on the discovery position. The time in the header is the start of the exposure and the world coordinate system in the header is accurate to 0.5". The files are 3 MB. The images are zero-padded to maintain the object in the center even if it was near the edge of the discovery image. Your browser may not bring up saoimage/ximtool automatically on the FITS file. Right-click on the link to save to local disk.

Moving objects are submitted to the Minor Planet Center at the end of each night. For those objects which receive a designation, we provide a link to query the MPC database - new objects are indicated with bold font. For those objects which do not receive a designation, we provide our own ASCII list of positions and times.

To make things considerably more exciting, we color code interesting transients using the following notation

Please acknowledge the Deep Lens Survey and NOAO when using the data for a publication. Comments and questions can be mailed to (tyson or dwittman) at physics dot ucdavis dot edu.