Principal Investigator Email Address
forster@mpe.mpg.de
Estimated Total Execution Time (hours, including overheads)
19.75h
General Description
This program consists of very deep ISAAC imaging with the narrow-band filter at 2.25um (NB225) to search for candidate Halpha line emitters at redshift z = 2.42 in the MS1054-03 field. - The survey area is 5'x2.5', covered with 2 adjacent ISAAC pointings, hereafter "NBF1" and "NBF2". - The pointings are separated by 2.5' (i.e. the ISAAC FOV), and each has P.A. = -30 degrees. - There are 10 OBs per pointing. Each OB consists of a sequence of 15 exposures dithered within a box width of 30" and with NDIT x DIT = 3 x 60s. The total execution time per pointing (including overheads and 1 standard star OB) is 10h, for both pointings it is 20h. - The NBF1 pointing has the highest priority: all the observations for NBF1 should be taken before those for NBF2. Sensitivity is a key parameter for our science goals, and with the full integration time obtained for NBF1, we would consider our program 75% complete. This program takes significant advantage of the existing very deep ISAAC Ks-band imaging in the MS1054-03 field (taken as part of the FIRES survey and described by Forster Schreiber et al. 2006, AJ, submitted; astro-ph/0510186). We will use these Ks-band data to subtract the continuum contribution from the NB225 images. Therefore, NO further imaging is required apart from the NB225 observations, making our program very efficient. The finding charts for the science OBs show the NBF1 and NBF2 pointings as squares on the Ks-band mosaic of 2x2 ISAAC pointings (which is 5'x5'; the NB225 imaging covers the north half of the Ks-band mosaic). The Ks-band mosaic is very deep, with a limiting magnitude of Ks(5-sigma, Vega) = 23.1 mag (6-7h integration time per pixel). To help during acquisition, the brightest sources (stars and galaxies with magnitudes in the range Ks = 13-17 mag, Vega) are marked with star symbols and circles. The brightest source in NBF1 is a star with Ks = 13.0 mag, and in NBF2 a star with Ks = 14.5 mag (Vega magnitudes; also indicated on the finding charts and in the 'User comments' field of each OB). The 10 science OBs for each pointing are named: ms1054_NBF1_1, ms1054_NBF1_2, ..., ms1054_NBF1_10 for NBF1, ms1054_NBF2_1, ms1054_NBF2_2, ..., ms1054_NBF2_10 for NBF2. For absolute flux calibration of the NB225 data set, we request that 1 OB per pointing is taken under photometric conditions. Clear transparency is acceptable for the other OBs. Accordingly, we have set the transparency constraint to "photometric" in the OBs ms1054_NBF1_1 and ms1054_NBF2_1. For each of these OBs, we provide a calibration OB to observe a standard star, named CAL_ms1054_NBF1_1 and CAL_ms1054_NBF2_1 (also specified in the "Calibration requirements" of the corresponding science OBs). A 2MASS K-band finding chart centered on the star position is attached to each calibration OB. For the other OBs, the transparency constraint is set to "clear". There is no preferred order in which to execute the OBs for a given pointing. Although we have prepared calibration OBs for standard stars, other stars observed as part of the ISAAC Calibration Plan in Ks would be suitable for our purposes and could be observed with the NB225 filter subsequent to the broad-band observations (see also the Special Calibration Information section of this README). The very deep ISAAC NB225 narrow-band imaging of the MS1054-03 field will represent a substantial extension to the existing very deep ISAAC Js, H, and Ks band mosaics (total of 80h integration time). The NB225 data will enable us to identify candidate Halpha emitters at z=2.42. These will constitute a key high-redshift population complementary to the Ks-band selected galaxies, in particular the massive and evolved z > 2 "Distant Red Galaxies" selected by their very red J-K colour. The coincidence of 4 massive DRGs at z = 2.42 (spectroscopically confirmed) within a few arcminutes in the MS1054-03 field signals a high over-density of galaxies. The Halpha emitters will provide a crucial new galaxy sample tracing the large-scale environment of massive galaxies and probing down the luminosity/mass function of galaxies at z = 2.42, in the early universe.
Waiver Requests
No Waiver Request was submitted
Critical Observing Condition Constraints
Transparency constraints: ------------------------ - 1 OB per pointing (2 OBs in total) in PHOTOMETRIC conditions for absolute flux calibration of the data set. - For the other OBs, CLEAR sky transparency is acceptable. Seeing constraints: ------------------ - Seeing conditions <= 0.8" as determined from the DIMM seeing monitor in the optical. This constraint is to match the image quality of the deep ISAAC Ks-band data that we will use to subtract the continuum contribution in the NB225 images, and to meet our sensitivity goals. Moon: ---- - A moon distance > 30 degrees is preferable. - We note that the moon comes closer than 15 degrees from the target fields for 1-2 nights during bright time.
Time-Critical Aspects
None.
Special Execution Requirements
None, except that all the observations for the Priority 1 pointing NBF1 should be completed before starting those for the Priority 2 pointing NBF2.
Special Calibration Information
No special calibration information really. We request 1 OB per pointing taken in photometric conditions. As detailed below, we have prepared 1 OB per pointing with "transparency = photometric" specified in the constraints set and the name of a corresponding calibration OB for a photometric standard star. However, we actually do NOT have a preference as to the standard star. Other standard stars observed in broad-band filter Ks as part of the ISAAC Calibration Plan on a photometric night would provide a suitable standard star for our purposes if also observed through the NB225 filter. The following provides detail on the science and calibration OBs provided. - 2 OBs have "transparency = photometric" in the constraints set, named: ms1054_NBF1_1: for the NBF1 pointing, ms1054_NBF2_1: for the NBF2 pointing. - For the other OBs, "clear" transparency is acceptable, and specified in the constraints set; these OBs are named: ms1054_NBF1_2, ms1054_NBF1_3, ..., ms1054_NBF1_10: for NBF1, ms1054_NBF2_2, ms1054_NBF2_3, ..., ms1054_NBF2_10: for NBF2. - 2 calibration OBs for observations of a standard star, which can be taken just before or after the OBs with "transparency = photometric": CAL_ms1054_NBF1_1: corresponding to the science OB ms1054_NBF1_1 for NBF1, CAL_ms1054_NBF2_1: corresponding to the science OB ms1054_NBF2_1 for NBF2. The calibration star is FS20 and is the brightest source (Ks = 13.5 mag, Vega) within an ISAAC pointing centered on the star. Two offset positions in the calibration OBs will include a galaxy (at 11:08:06.03, -05:10:01.9) which has a 2MASS Ks magnitude of 12.2 in a 14"x14" aperture, and in which the brightest compact sources from the 2MASS PSC catalogue have magnitudes of 13.4.
ToO Information
N/A.
ToO Activators List
N/A.
Is this a Pre-imaging run ?
false
Pre-imaging Requirements
N/A.
Source(s) of Pre-imaging
Pre-imaging sources not listed above
Do all your OBs comply with the instrument-specific requirements listed on the instrument-specific Phase 2 web page ?
If this is a pre-imaging run, did you select PRE-IMAGING for the Observing Category for each Observing Template ?
N/A
Do all your finding charts comply with both the general and instrument-specific Phase 2 Web Pages ?
If you submitted OBs for standard stars, did you specify the magnitude and spectral type of all standard stars in the OBs ?
Have you included OBs for any calibrations that you need but which are not part of the Calibration Plan ?
If you are observing Moving Targets, have you attached suitable ephemeris files to your OBs?
N/A
If you have preferences which OBs should be executed first, did you make use of the User Priority field in the OBs ?
If this is a run that requires coordinated observations with other facilities, did you give proper instructions in the Time-Critical Aspects Section ?
N/A
If you submitted OBs for standard stars, did you use the provided StandardStar templates ?
If you are using a specific offset pattern or position angle, did you check carefully the definition in the manual ?
If you are doing spectroscopy, did you draw the slit on the Finding Charts ?
N/A
Did you enter the magnitude of the brightest star in the field-of-view in each OB ?
If you use the MoveToPixel acquisition, have you given clear instructions on the FC and in the OB comment section as to how the field should be centered ?
N/A