Skip banner and navigation tools.

 |  site map

Skip sidebars of related page links.

Targets of Opportunity

Although Swift's primary mission is to detect GRBs and observe the X-ray and optical afterglows, the satellite is also well designed for observing other transient astrophysical sources. Previous Targets of Opportunity (ToOs) have included supernovae, cataclysmic variables, active galactic nuclei and comets.

Swift possesses certain attributes which make it suitable for a wide range of ToO requests:

Commands can be uploaded to Swift within a matter of hours, where appropriate. More commonly, ToOs are discussed at the daily planning meetings and inserted into the schedule when possible.

ToOs may not impair Swift's capability to respond to GRBs. They should make use of more than one instrument and the target should be more than 46 degrees from the Sun in the sky, as well as more than 21 degrees from the Moon (see the Sun and Moon Angle Calculator) and 6 degrees from the orbit pole. Requests that satisfy these criteria and are for durations between 1 and 20 kilo-seconds have a good chance of being accepted for observation; ToO requests at a high hour angle from the Sun are most preferable, however, particularly those at greater than 9 hours. Only a brief proposal of a few paragraphs is required, within which the requested observing time should be justified.

To request a Target of Opportunity (ToO), or for more details, please visit the Penn State ToO website at: Alternatively, contact the UKSSDC via e-mail at, or by phone on +44 116 223 1706 (during office hours).

Note that very bright optical sources can deposit significant charge in the CCD pixels, so affecting the on-board pattern recognition of X-ray events. This PDF file shows the expected number of photons per pixel for a range of star magnitudes; those highlighted in green are expected to be acceptable and should not produce optical loading problems. Please check for bright optical sources in the field of view of your desired ToO. Also see the information on the magnitude limits for safe UVOT observations

If the error region of your source is larger than the XRT field of view (a diameter of 23.6 arcmin), there is a possibility to perform tiled observations.