README web version of /home/usg/OPS/MTS/readme_xml/readme_84078300
Principal Investigator Email Address
Estimated Total Execution Time (hours, including overheads)
General Description
This README is valid for programmes 084.C-783(A+B) and 084.C-789(A+B),
which comprise
a monitoring programme of the T Tau system at near- and mid-infrared wavelenghts
with NACO and VISIR (084.C-0783), and and optional TOO programme perfoming the same
observations with denser time sampling in case strong variations are detected during
the normal monitoring campaign (084.C-0789). The main monitoring programme 074.C-0783(A+B),
consists of "monthly monitoring" for the whole of P84 (except for march) and two
months
of more intensive "weekly" monitoring (preferably november+december).
intro and some numbers:
The T Tau system harbors 3 known young stars with circumstellar disks, of which
only the
northern one ("T Tau N") is optically visible. The southern "infrared companion"
T Tau S
(~0.7 arcsec south of T Tau N) is a close binary consisting of Sa and Sb (separated
by
approximately 125 mas). Sb is only mildly variable (~0.2 mag RMS in K-band). Sa
is strongly
variable (total amplitude >3 mag at K, fastest recorded variations ~1 mag in
1 week at K,
0.26 mag in 3.9 days at 12.8 micron).
The main purpose of this programme is to characterize the variability of SED of
Sa (and Sb),
by means of (near-) simultaneous near- and mid-infrared imaging (with NACO, and
VISIR).
Simultaneously, the strength of the Bracket gamma emission line will be monitored.
approximate fluxes to be expected are:
T Tau N: K=5.52, F(12.8)=8.2 Jy
Sa: total amplitude 6.0
Waiver Requests
Critical Observing Condition Constraints
Time-Critical Aspects
This "normal monitoring" part of our programme (as opposed to the TOO
part,
084.C-0789(A+B)), consists of a "monthly" NACO+VISIR observation for the
whole of P84, and a "weekly" NACO+VISIR observation for 2 months during
this period (preferably november+december).
For both the "Monthly" and "Weekly" part of the monitoring programme, it
is not needed to have the observations interspaced by exactly one month
or exactly one week. Intervals of 1 month +/- 1 week, and 1 week +/- 2 days
are a good guideline and allow for a reasonably relaxed schedule.
It is much more important, that the near- and mid-infrared (NACO and VISIR)
observations of each epoch are performed (quasi-) simultaneously, whenever
possible during the same night. If, for example, practical issues on the
mountain make it impossible to perform "simultaneous" NACO/VISIR observations
during the week T Tau "is due", whereas this can be done one week later, then
it is better to postpone the observations to that time.
Scientifically, there is no preference for when to do the 2 months of weekly
monitoring - we don't know when (and whether, for that matter) Sa will show
strong photometric variablity. From a practical point of view, we prefer the
"November+December" period, as Taurus is optimally visible then, and it
leaves time for data analysis prior to proposal deadlines.
Special Execution Requirements
Since this is a monitoring programme in which we are seeking to characterize
apparently random and unpredictable brightness fluctiations in Sa, the
campaign involves some "near-realtime decision making". This means that we
should do a quick first analysis of the data (within ~1 day), in particular
during the two month period of "weekly monitoring".
Though direct interaction with PI's is not part of standard procedures, we would
greatly appreciate it if you could send us (boekel@mpia.de, ratzka@usm.uni-muenchen.de)
a quick email saying "we observed T Tau last night with NACO (VISIR)", in case you
did.
Spectroscopy: The acquisition has been setup such that we center the bright
T Tau N in the slit, and then offset to the south such that Sa and Sb fall
into the slit. Please make sure that the offset coordinates as given in the
OB correspond to what is indicated in the spectroscopic finding chart, in
particular with respect to the sign of "Alpha Offset". The slit should be
centered at Sa (i.e. 0.09995 arcsec WEST and 0.64785 arcsec SOUTH of T Tau N).
The position angle should be such that Sb also falls into the slit
(i.e. 139.014 degrees East of North, assuming 0 degrees corresponds to a
north-south orientation).
Special Calibration Information
We will perform relative photometry between N, Sa, and Sb, and thus we
require no special
photometric calibration beyond what is done by default.
For accurate astrometry (orbital fitting of Sa-Sb), we require the observation of
an
astrometric standard field during one of the later epochs.
ToO Information
ToO Activators List
Is this a Pre-imaging run ?
Pre-imaging Requirements
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 ?
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?
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 ?
If you have PSF reference star OBs, do the names of those OBs begin with
PSF_ ?
If there are Finding Charts attached to your OBs, is the field-of-view
of at least one of these charts 2' x 2' (with clearly labelled field orientation)
?
Have you clearly marked and labelled your wavefront reference objects
R1, R2, R3, ... (as specified in the NAOS Preparation Software) on your Finding
Charts ?
Have you specified the magnitude of the brightest object in the field-of-view
for each OB ?
Are there objects in any of your fields (including standard stars) which
are brighter than the limits specified in the User Manual and on NACO web Pages
?
If the previous answer is yes, have you given a list of OBs and a justification
for the brightness limit violation in the general description field ?
Last creation of page: Tue Oct 6 15:40:32 2009
If you have comments, please contact usd-help@eso.org