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UKIRT Newsletter : Issue 4 : UKIRT News
UKIRT NEWS
UFTI Report
Sandy Leggett
UKIRT, Joint Astronomy Centre, HIlo, Hawaii
| UFTI - the UKIRT Fast Track Imager - obtained first light in
October 1998. Since the telescope commissioning the instrument has unfortunately
been plagued by poor weather (hindering photometric calibration) and with
filter motor problems. In January 1999 it was brought down to the lab in
Hilo and the motors repaired. At the time of writing it is in transit back
to the summit. The hardware should behave much more robustly after the
recent engineering. While UFTI was in the lab some software bugs were identified
and fixed. There are some other software issues still to be addressed,
but the data acquisition should also behave much more robustly, and be
faster, since this recent engineering period.
The UFTI background levels are much lower than IRCAM's due to the smaller |
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pixel scale, the lower read-noise, and the lower quantum efficiency
of the detector at wavelengths shorter than H. In these very low background
conditions we see occasional apparent changes in bias levels resulting
in peculiar structure at the 20-30 DN level. These are being investigated
further, but in the meantime it is recommended that observers use the multiple
reset (flush) mode which reduces some of the problems.
Also, the array suffers from charge persistence resulting in remnant
signals at the 0.3% level. These take about 10 minutes to disappear, but
you can reduce the problem by shifting targets to different regions of
the array, blanking off the filter wheel at the end of your exec, and taking
extra darks where time permits. We are working on implementing the shutter
for UFTI which should reduce the problem further.
(The engineering was successful and UFTI is now performing well -
Ed.) |
Science Highlights
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| Despite these problems the first paper using UFTI data has been
submitted to Astrophysical Journal. This paper, by Frayer et al.,
reports on UFTI and SCUBA observations of the luminous interacting galaxy
pair VV114 (Figure 1). Good correlations were found between the spatial
distribution of the sub-mm and CO emission, and both match the reddest
(eastern) component of the pair as demonstrated by UFTI. A higher dust
mass than implied by the IRAS data alone is derived and suggests that the
system will evolve into a compact starburst, similar to Arp220. |
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Figure 1: A J-K image of interacting galaxy pair VV 114, taken using
UFTI in October 1998. These observations showed the presence of a very
red compact region in the eastern component of VV 114 which is thought
to be associated with a dust rich region of intense star formation.
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Figure 2: The HH 7-11 outflow. The image was taken through the
H2
filter using UFTI. By comparing to observations which were
taken 4 years earlier, proper motions of the different shocked components
of the flow were measured, revealing velocities exceeding 400 km s-1.
(Image courtesy of Jason Hobson, Antonio Chrysostomou & Chris Davis).
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| During the successful live broadcast of UFTI observing
to the UKATC in Edinburgh in celebration of its opening (see this issue's
Top
End), a number of observations were taken of various outflow sources.
The image obtained of the Orion "bullets"
can be seen on the front cover of this Newsletter. Figure 2 shows the image
which was obtained of the outflow HH 7-11, in Perseus. The structure revealed
in the leading bow shock was quite detailed, and was highlighted in the
insert to the last Newsletter.
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Comparisons to data of the same source that were obtained 4 years earlier,
using IRCAM3, allowed proper motions of the H2 shocks to be
measured. The proper motions showed that most of the shocks are moving
in excess of 400 km s-1, a velocity which far exceeds the dissociation
speed of the H2 molecule. A paper is being prepared for publication. |
| Finally, some interesting work is being conducted by Phil Lucas
and Pat Roche, of Oxford University, in their search for Brown Dwarfs.
In the last few years, a significant number of genuine brown dwarfs have
been discovered, both in galactic clusters and in large area surveys of
the solar neighbourhood - DENIS and 2MASS. Brown Dwarfs are brightest when
they are very young and it is clearly important to search for the sub-stellar
population of pre-main sequence objects in star formation regions in order
to study the evolution of the population.
The flux from brown dwarfs peaks in the J-band, and in clusters
with low extinction they appear bright in the J-, H- and
K-bands,
but are much fainter at optical wavelengths. |
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Figure 3: The J2/IH image brings out cool sources, such
as the brown dwarf candidate shown here _ the right-hand star of the two
at the top of the image. The holes in the image are nearby blue/red stars
(Image courtesy of Phil Lucas & Pat Roche).
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| UFTI contains specially commissioned filters designed for the study
of cool objects. These are a long I filter (0.78 - 0.93 microns)
and a broad Z filter (0.85 - 1.05 microns). These filters sample
the steep rise in flux from optical to infrared wavelengths, providing
the temperature sensitivity which is lacking in the traditional infrared
filters. Hence the deep survey of the Trapezium cluster in Orion by Lucas
& Roche, in the I-, J- and H-bands |
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provides both extinction corrected luminosities and temperture information.
Figure 3 shows a brown dwarf candidate which has already turned up from
their survey. The figure is a subset of their data set, where a J2/IH
image has been formed to increase the contrast for cool objects. The star
to the right of the pair is flagged as a brown dwarf candidate. |
View from the Top
Thor Wold
Telescope Systems Specialist, UKIRT, Joint Astronomy Centre,
Hilo, Hawaii
| Here it is, another year. The grounds of the Beautiful Vacation
Resort Hale Pohaku continue to look somewhat peaked, but moisture has finally
found its way to the area. Come spring, I expect this year the wildflowers
and the mamane trees will really bloom to make up for last year. It has
been so dry in the upcountry that the State shut down Mauna Kea State Park
(the campgrounds just the Hilo side of the Pohakuloa Military Base) because
the spring that supplied water to the site dried up. I believe this has
never happened before. I hope the recent moisture replenishes the source
enough to re-open the campgrounds.
This is supposed to be a La Niña year; more wet and cold than
usual, but to this writing (into February), our weather loss stats are
not abnormal. It has snowed at Hale Pohaku, but only one heavy bout of
snow that managed to close the road a couple of days. We do still have
two or three more months to go, though.
Your Beautiful Vacation Resort Hale Pohaku has been really crammed to
the ceilings the past few weeks. Subaru has gotten first light, but we
were overrun with the NHK TV people, who were going to stage another first
light to be broadcast live to Japan. HP actually overflowed and some of
them spilled over to the Construction Camp downhill. That, coupled with
Gemini having extra personnel staying on the mountain as they near firstlight,
absolutely crammed HP. One day recently, the cooks said they had 80 dinners
to make and 73 people staying overnight. It was almost as bad as it was
for the eclipse. This made for some noise in the dorms and crowding during
dinnertime.
The lack of visitors using HP was the reason for the onerous cutbacks
on service last year. One would think that now that the place is again
teeming, we would see some restoration of thingscut back on, but nobody
is holding their breath. In fact, the number of grumblings about the situation
has lately seemed to increase.
The improvements to the Saddle Road between the 19 and 23 mile markers
have been completed. This certainly makes the journey up the mountain easier
and safer, but now it makes the section between the 23 mile mark and the
MK turnoff look bad! I still remember when that was the only section above
the 10 mile mark that was decent! |
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Debate continues over the overall realignment and improvement of the
Saddle Road. It appears the Environmental Protection Agency is going to
be satisfied about the `loss' of `wetlands' (see View From the Top in the
last Newsletter), so planning can continue. It looks like the project may
start in the year 2000 with phase one; the realignment of the two ends
of the road. On the Hilo side, this will coincide with the Puainako Street
Extension project. This will mean travellers coming down the mountain will
no longer have to travel down Kaumana Drive, but rather can go down the
new Puainako Street from the 6 mile mark on Saddle Road. This will meet
Komohana Street one block south (Puna direction) of the UHH Science Park,
so all you would then have to do is turn left and be at the office. The
reverse would be true for going up the mountain. We kama'aina have been
waiting on these projects for over 30 years!
At the telescope, UFTI finally arrived but has gone through some teething
pains. We had trouble with the filter wheels, which at this writing we
hope we have fixed. It is hoped UFTI is in action in March. I am anxious
to see if UFTI can properly sample what the upgraded UKIRT can accomplish
with image quality (see our web page: `Could
these be the best ground based images ever?'). We have even surprised
ourselves on this!
During the winter months, the Dome Ventilation System tends to get iced
up. It appears we may well have to not use it at all, but during the winter
months, the dome does cool down faster and better than in summer.
We are intending to refurbish the control room this summer: repainting,
recarpeting, new shelves and counters, etc. New chairs have already arrived.
These are dangerous! They are so comfy that staying awake will definitely
be a problem! Perhaps we ought to finally get theTSSs some electric cattle
prods to help keep the observers awake...then again, the observers may
well have to keep the TSSs awake. That is how good these chairs are. We
hope the entire project makes for a more pleasant experience.
Aloha! |
The New UKIRT Archive
Paul Hirst
X-Ray Astronomy Group, Dept. of Physics & Astronomy,
University of Leicester, UK
| Since the 10th March, I have been placed at the Joint
Astronomy Centre as part of my PPARC PhD studentship under a program
enabling PPARC graduate students to take up Long Term Attachment
funding to work on their PhD research for a period of 2 - 3 months. My
work here centres on mining the UKIRT archive to obtain a comparison
data set as part of my research into Narrow Line Seyfert 1 galaxies,
the main topic of my PhD thesis at Leicester University. I've also
been helping out in loading data into the archive and preparing the
archive for release on the WWW. At time of writing, the archive goes
back to early 1994.
The new
UKIRT archive, like most telescope data archives, is based around
an SQL database interfaced to the World Wide Web. Data from image
headers and the TSSs log are stored on-line and can be searched
interactively through a WWW form, which is interfaced to the SIMBAD
name resolver to add the ability to search by object name,
independently of the name the observer gave to the target. This also
includes a `search radius' feature, so serendipitous observations of
your target within a field will be found as will observations based on
slightly different co-ordinates. Searches can also be constrained by
instrument (currently, only CGS4 and IRCAM3 data are online), by any
of the FITS headers found in UKIRT data files and by weather and
observing conditions data from the TO's log. Part of the main archive search form (the `common' form)
showing a typical search, is shown below. Full details of the inputs
to the form are given on the help page, the specifications for a given
field can be quickly found by clicking the label of the field, then
using the browser's back button to return to the form. |
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A search of the archive will generate a web page containing a table
summarising the data files which match the search criteria. The fields
to be displayed in the summary table can be selected using the toggle buttons
to the left of each field in the search form. The full list of common and
instrument specific headers, as well as entries in the TSS's log for the
night can be displayed for a file in the results table by clicking the
more,
inst
or
log tokens in the table (see figure below).
Each file also contains a toggle button to mark it for retrieval from the
archive. After marking the datasets to be retrieved, clicking the Request
marked datasets button will bring up a page asking for your contact
details (name, institution and E-mail) along with a final list of what's
been selected, with the opportunity to de-select any unwanted files,and
a submit button. Submitting the request will file it with the database
system, returning you a request ID as confirmation.
The actual UKIRT data files are now archived to DLT cartridges; JAC
staff will read your data from tape and E-mail you with details of collection
- be it via FTP or a data tape in the post.
Normally, your dataset will include the full compliment of files copied
down from the summit - i.e. the raw idir and odir files,
along with the `user-friendly' rodir and rgdir files, though
occasional nights affected by network or computer problems may just contain
the idir and odir files - the cgs4dr or ircamdr software
packages can be used to regenerate the rodir and rgdir files
in the usual way.
When retrieving data from the archives, remember to make sure you obtain
the necessary calibration data. Searches based on run number can be useful
for selecting these calibration runs. |
The common form to the UKIRT archive interface.
(click on the image to view it in full size)
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The results form of the UKIRT Archive, showing results of a search
and options to interrogate the instrument headers and the TSSs log.
(click on the image to view it full size) |
Electronic Submission of PATT Proposals
| From the 1999B Semester onwards, as directed by the UKIRT Board
at its last meeting, all proposals for UKIRT time must be submitted electronically.
To try to ensure future compatibility with other telescopes, we have adopted
the Latex style file and web-based uploading method which has been in use
at the AAO for the last few semesters.
The process is reasonably self-explanatory, and documented on the webpage,
which is linked to from the UKIRT home page.
After some introductory text you are presented with links to the latex
template (you modify this file to reflect your proposal), and to the required
style file which latex will use when processing your template. Note that
this is not the formload system, although filling out the latex template
is a similar process to filling out a formload template. Graphics have
to be included via encapsulated postscript files (optionally gzipped).
Instructions written by Stuart Lumsden for the AAO system are linked to
from the submission page, and style files for two different methods of
embedding encapsulated postscript are again made available by links. Please
use the style files unchanged; we will be using the same files stored locally
when processing your proposal, so any changes you make will not be reflected
when your proposal is printed at the JAC. If you encounter any problems
with the system, please contact Andy Adamson (adamson@jach.hawaii.edu) |
People
Arrivals
Malcolm Currie has arrived from Starlink to as a data reduction
programmer for the ORAC project. Malcolm initially spent a few months at
the UKATC in Edinburgh familiarising himself with the project before coming
out to the JAC.
Dwight Chan recently joined the UKIRT staff as an electronics
engineer. Previously, Dwight worked for the JCMT. |
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