README web version of /home/usg/OPS/MTS/readme_xml/readme_60942100
Principal Investigator Email Address
Estimated Total Execution Time (hours, including overheads)
General Description
We propose X-shooter observations of the proto-quasar
candidate PKS1549-79 (z = 0.152), which fulfills all the critera for
an object in which both the supermassive black hole and galaxy bulge
are growing rapidly via merger-induced gas accretion. The observations
will be used to: (a) accurately determine the properties of the
obscured AGN (reddening, luminosity, black hole mass, Eddington ratio); (b)
determine the energetic significance of the AGN-induced outflows.
Technical details.
- Spectrophotometry. In order to achieve the science goals we require high accuracy
mearsurements of a wide range of emission lines, as well
as of the continuum SED, covering the full spectral range of 330 - 2400nm.
Therefore spectrophotometric accuracy (to ~5%) is important for this project
and we require a relatively wide slit (~1.5-1.6) to avoid the
differential slit losses with wavelength becoming too large. Note
that the target is dominated by emission lines and a relatively faint
stellar continuum at optical wavelengths, but is much brighter in the
near-IR (H-K bands) where the obscured quasar nucleus becomes visible.
- Slit PA. Because the target is relatively southerly (Dec -79 degrees)
it is close to the limit of the ADC, even when observed at optimum. Therefore
we would prefer to have the slit PA set to the parallactic angle of the middle
of the observations (i.e. ~45 - 50 mins after the start), in order to ensure the
best possible spectrophotometry. Attached to the OB (as an additional
"finding chart") you will find a target visibility plot for August that
shows the altitute of the source for various sidereal times, with the parallactic
angle marked (60.A-9421_vis_aug.jpg). This should allow easy estimation of the parallactic
angle
for the middle of the observations (it only needs to be set to ~10 degrees accuracy).
- Observing period. The target should be observed in August, since it will be
too low at the end of September.
- Exposure times. The exposure times are set by the optical (where the source
is faintest). In order to achieve our target S/N we require a total exposure time
of 5400s in the optical, although this will be split across several
exposures in the nod pattern. *Note that the object appears much brighter
in the near-IR than it does in the optical, because the obscured quasar
nucleus becomes visible at near-IR wavelengths.*
- Nodding. In order to ensure accurate sky subtraction in the red and near-IR
we require the source to be nodded along the slit. A 5 arcsec nod throw is
probably optimum for this source in order to avoid any overlapping of the
emission from the host galaxy.
- Template: SHOOT_slt_obs_AutoNodOnSlit
- Total time for observing block. Using the example in section 3.1.4 of
the Xshooter manual I estimate:
* Pointing/acquisition/SLIT setup: 360+180+30s=570s
* At eack pointing: UBV:1x(675+22)=697s; VIS: 2x(338+27)=730s;NIR: 3x(225+0.88)=678s
* Slowest arm: VIS (730s). Therefore the total integration and
readout time is: 8x730=6570s
* Total telescope offsets: 8x15=120s
* Total execution time on main target: 570+6570+60=7260s
Special Execution Requirements
==============================
Please set the slit PA to the parallactic angle at the middle of the
observations (~45 to 50 mins after the start) -- see file
60.A-9421_vis_aug.jpg for parallactic angle estimates.
Waiver Requests
The total intergration time is ~1.5hr for the main target OB. Therefore,
rather then split into two observing blocks, for reasons of effciency, I'd like
to keep it simple as one observing block. Our waiver request for this has been approved.
Critical Observing Condition Constraints
Time-Critical Aspects
Special Execution Requirements
Special Calibration Information
- We assume that spectrophotometric flux calibration standards will be
observed
with a wide slit at least once a night as part of the standard calibration plan.
By combining flux calibration star observations from all the nights in the run,
it should
be possible to achieve a relative flux calibration accuracy of ~5%. However,
to make absolutely certain please observe an extra flux standard star with a wide
slit on the night of the PKS1549-79 observations -- this will take about 10 minutes
and is already accounted for in the 2.5hr total execution time for the project.
- To correct for atmospheric absorption features I require observations of a telluric
standard star as close as possible to the target in position and time. For this
purpose I have selected the F0 star HD138710 (coordinates given below). Using
the ECT I estimate that 4x10s exposures in the NIR and VIS arms (in ABBA pattern)
will give sufficient S/N without saturating the detector.*Please observe the telluric
star with exactly the same slit, detector setup and PA as the main target.*
Coordinates of HD138710 (J2000)
RA 15 44 09.754
Dec -80 20 31.17
V=10.07
H=8.70
I estimate the observations of this source will take ~10 minutes including acquisition.
(This should be the brightest object in a 2x2' field)
ToO Information
ToO Activators List
Do all your OBs comply with the instrument-specific requirements listed
on the instrument-specific Phase 2 web page ?
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 specified the S/N ratio at given wavelength in the User Comments
field of each OB?
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 ?
Last creation of page: Tue Oct 6 15:40:06 2009
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