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The Rapid Response Mode

IMPORTANT NEWS: Starting in P109, it is now possible to trigger a RRM even if the desired instrument is not the one in operations. That is, the RRM trigger can also automatically make a focus change so that the desired instrument is chosen. See below for details.


This page provides information about the Phase 2 preparation of approved programs that require the use of the Rapid Response Mode (RRM), and specifies the guidelines for activation.

Rapid Response Mode: Introduction

The RRM at the VLT allows the automatic trigger of observations of transient phenomena requiring almost immediate follow-up, such as gamma-ray bursts, novae, or supernovae. It works as follows:

  • An observation trigger signal is sent via an ASCII file to the ftp server acftp.hq.eso.org, requesting the execution of a specific Observation Block (OB).
  • A programme at the telescope is continuously monitoring the dedicated ftp directory.
  • When a valid trigger signal is found in the ftp directory the on-going observation is ended, the telescope automatically presets to the coordinates specified in the ftp file, and performs the requested observations as specified in the trigger signal.

Note: Please consider that RRM OBs use a special template and can only be triggered through the RRM procedure. Any OBs that follow an RRM trigger, including those intended to be executed immediately after the RRM OB, must be submitted as normal ToO OBs. RRM and ToO OBs must be prepared and submitted in separate observing runs.

RRM Phase 2 Preparations

  • Once a RRM proposal is approved, a complete Phase 2 package (Observation Blocks and Readme file) needs to be submitted to ESO following the standard Phase 2 preparation procedures. In particular, please note that the deadline for the submission of the Phase 2 package applies for RRM runs as well.
  • The names of OBs for execution in RRM mode must be preceded by the RRM_ prefix (e.g. RRM_grb346+580_3x600s). They should not contain any spaces or special characters, but only letters, digits, dashes, plus signs and/or underscores. The name of each RRM OB in a given run should be unique, multiple RRM OBs with the same name will prevent their triggering.
  • RRM OBs should not be organized in scheduling containers, but rather be loose OBs. If they are in scheduling containers it will not be possible to trigger them.
  • Once an activation has been successfully triggered, the OB executed cannot be used for another activation.
  • Besides the RRM OBs, the users should also prepare normal ToO OBs in case non-RRM follow-up observations are required (since with RRM only one OB can be activated), or if observations of the target are desired when the 4-hour RRM deadline has passed (see below). These ToO OBs should be prepared and submitted during Phase-2 in a separated run from the RRM one.
  • The ESO User Support Department verifies the submitted material. The account_id used to create the activation file as well as the host name, username, and password used for uploading it will be communicated by Paranal to the Principal Investigator of the programme during the start of the period or in due time in the case of a DDT programme.

Information regarding RRM Activation

  • To activate the RRM, an ASCII file must be received at the dedicated ftp server in Garching with the following characteristics:
    • Its name must be the same as that of the OB that needs to be executed, preceded by a string of the generic form [instrument]_[account_id]_[OB] (e.g. UVES_5291_RRM_grb346+580_3x600s). Your account ID is not your User Portal username, but rather a number which will be supplied to you by the Observatory at the start of the new Observing Period (or in due time if yours is a DDT programme).
    • Its content must be a single line with the J2000.0 coordinates of the target. The format is hhmmss.ss for the right ascension, sddmmss.s for the declination (e.g. 004727.32 -251738.3). A flag ('T') may also be added at the end of the line, in case the PI would like the trigger to take place even if the required instrument is not currently in operations. Thus using <ra> <dec> T  would activate the option for the change of focus. This will require an additional 5 minutes for the change of focus, so this should be done only when this overhead is not an issue. The default value of the flag is F(alsie) and the flag is optional.  If not present, the default value is taken (F, no change of focus).
  • The activation file must be uploaded to the relevant instrument sub-directory, such as:
    • ~/UVES/ for UVES activations,
    • ~/FORS2/ for FORS2 activations,
    • ~/MUSE/ for MUSE activations,
    • ~/HAWKI/ for HAWK-I activations,
    • ~/XSHOOTER/ for X-SHOOTER activations (Note that XSHOOTER must be used as [instrument] for the file name.)
  • Along with the RRM trigger signal, accompanying RRM information, including a finding chart, must be sent to Paranal:
    • For Paranal, use this email template, with these specific requirements. The e-mail must be sent to esorrm@eso.org. Do not attach the finding chart to the email
    • The finding chart must be sent via email to the specfic telescope account.
    • Fallback-approach: If no automatic acknowledgement is received from the above procedure within 15-20 minutes, send a simple activation email (to either antu@eso.org for UT1, kueyen@eso.org for UT2, melipal@eso.org for UT3, or yepun@eso.org for UT4) with the finding chart attached.
  • Only requests from the end of evening nautical twilight to the beginning of morning nautical twilight (i.e., received when the Sun is more than 12 degrees below the horizon) will activate the RRM.
  • It is the responsibility of the activators to ensure that the target is observable, bright enough, and easy to identify by the night astronomer.
  • Any successful activation will be counted as an RRM trigger, whether the requested observations could be successfully performed or not.
  • RRM activations will be accepted during both Service and Visitor Mode runs: they have overriding priority over other observations. The only exceptions are cases in which the OPC have granted a 'protected status' for Visitor Mode observations of events with exceptional characteristics. ToO observations immediately following the RRM ones have the same override status over Visitor Mode.
  • There is no need for the requested instrument to be currently in use. The addition of the T flag at the end of the trigger (see above) can be used to request a change of focus, with an estimated overhead of 5 minutes.
  • An RRM trigger can only be activated up to 4 hours after an event. After this deadline observations should be requested through normal ToO triggers.
  • Any desired immediate follow-up observations of a successful RRM trigger must be requested through the normal ToO procedure, since only one OB can be executed as RRM. Such a ToO request can be already specified in the RRM alert email, or in a separate ToO request. Also in this case, ToO OBs must have been prepared before the Phase 2 deadline for this to be possible and should have been submitted in a separated run from the RRM one. The execution of such follow-up observations cannot be guaranteed.
  • RRM and ToO data will be made available immediately to the PIs and their data delegates through the ESO archive via the User Portal.
  • For all RRM programmes the default (12 months) proprietary period will apply, unless a shorter period has been specified in the Phase 1 proposal.
  • Any intentional misuse of the RRM (e.g. for the observation of events unrelated to the science case in the approved proposal or for late-time follow-up not justifying the use of the RRM) will result in the cancellation of the program in question.

Time accounting

  • The time accounting is performed in the same way as for normal ToOs; if a program has used up all its hours, irrespective of the number of (RRM) triggers executed, no more triggers will be accepted.
  • The time used by a RRM is counted from the start of the OB that was interrupted until the start of the first OB after the RRM OB.

Checking the status of the RRM system and of activation requests

The state of the RRM process, and the result of an activation, can be followed on one of these webpages:

The delay is of the order of a few minutes. Requests will only be executed if the RRM state is ONLINE.

Instrument selector

This page is valid for all instruments