The ISOPHOT team have developed new recommendations for observing faint sources with ISHPOHT which involve small rasters rather than chopping. This was finalized around Feb 1997 and following this we re-designed the observations for the remainder of our observing time. We had put our program on hold in September when it became clear that chopped observations had major problems. The revised program, which included re-observation at long wavelengths using rasters for a number of high-priority targets and re-specification of new observations of others, was released in April 1997. The latest prediction for the satellite lifetime has extended its life until April 1998. Our project has been allocated a 15% increase in our observing time as a result of this life extension. We are currently working on setting priorities in order to determine which targets to include in this additional time. This will help to offset some of the targets lost due to the significant decrease in detector sensitivity over pre-flight predictions

Wilkes, Belinda J.

English

NASA Technical Reports Server

NASA-CR-205212
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..... , ..... ISO KEY PROJECT: c-_ .'/ ",7- .)z_
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_ _':?;-i i _L THE FULL RANGE OF QUASAR/AGN PROPERTIES
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NASA Grant NAG5-3363
Annual Report
2
For the Period 1 September 1996 through 31 August 1997
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• Principal Investigator
=- , Dr. Belinda J. Wilkes
....... C -
= August 1997
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-National Aeronautics and Space Administration
Washington, DC 20546
Smithsonian Institution
: Astrophysical Observatory
- Cambridge, Massachusetts 02138
" " _]-The Smithsonian Astrophysical Observatory
_ ] is a member of the
- l.H vard-Smithso i Centerfor Astrophysics
o - ?
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The NASA T_ 0tficer for this grant is Dr. Donald West, Code 681, Lab for Astronomy
• L-_ & Solar Physies,-_N_ti-oaal Aeronautics and Space Administration/Goddard Space Flight
-=_ q-;_ Center, C-azen__20771.
. =-
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Contents
1 TASK A -- P.I.: B. Wilkes
2 TASK B -- P.I.: J. McDowell
3 TASK C --P.I.: J. Stauffer
4 TASK D -- P.I.: S. Willner
5 TASK E -- P.I.: J. Moran
6 TASK F -- P.I.: P. Myers
7 TASK G - P.I.: M. Ashby
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2
3
5
5
5
6
1 TASK A -- P.I.: B. Wilkes
Data Analysis
The PIA (PHOT Interactive Analysis) software was installed on the HEAD SUNs and
updated a number of times during the year as upgrades became available. We have learned
how to use this software and begun analyzing our data. We have concentrated on observations
with long (>256sec) exposure times to avoid the most extreme detector responsivity drift
problems which occur with a change in observed flux level - ie. as one begins to observe a
new target.
There remain a significant number of problems with analyzing these data including:
• the default calibration source (FCS) observations early in the mission were too short
and affected by strong detector responsivity drifts
• the calibration of the FCS sources is not yet well-understood, particularly for chopped
observations (which includes most of ours)
• the detector responsivity drift is not well-understood and models are only now becom-
ing available for fitting chopped data
• charged particle hits on the detector cause transient responsivity drifts which need to
be corrected
the "flat-field" calibration of the long-wavelength (array) detectors: C100, C200 leaves
significant residual structure and so needs to be improved
the vignetting correction, which affects detected flux levels in the array detectors, is
not yet available
• the intra-filter calibrations are not yet available
• The background above 60 microns has a significant gradient which results in spurious
positive and negative "detections" in chopped observations.
As a result of these various problems, data analysis has proceeded slowly and we still do
not have fluxes which are known well enough to address our main scientific questions.
Drs. Belinda Wilkes and Kim McLeod attended the workshop "Taking ISO to the Limits"
at VILSPA, Spain in February. Dr. Wilkes presented initial results on low and high redshift
quasars and discussed the problems which still remain in analyzing the data. They then
visited the ISOPHOT data center in Heidelberg, Germany to discuss these problems and
possible solutions with the ISOPHOT team. This visit improved the situation for: removing
transients, correcting for vignetting. We also put together a plan for subtracting the back-
ground in the C100 detector which will allow us to correct for the background gradient and
the pixel-to-pixel variations in the detector. We discussed the possibility of using DIRBE
and IRAS data to provide an independent calibration of the background flux from 12-100
microns. Dr. Kim McLeod visited IPAC in July to discuss these latter two possibilities and
we are currently investigating them further.
ISO Observation Planning
The ISOPHOT team have developed new recommendations for observing faint sources
with ISHPOHT which involve small rasters rather than chopping. This was finalized around
Feb 1997 and following this we re-designed the observations for the remainder of our observing
time. We had put our program on hold in September when it became clear that chopped
observations had major problems. The revised program, which included re-observation at
long wavelengths using rasters for a number of high-priority targets and re-specification of
new observations of others, was released in April 1997.
The latest prediction for the satellite lifetime has extended its life until April 1998.
Our project has been allocated a 15% increase in our observing time as a result of this life
extension. We are currently working on setting priorities in order to determine which targets
to include in this additional time. This will help to offset some of the targets lost due to the
significant decrease in detector sensitivity over pre-flight predictions.
Conferences and talks
Dr. Wilkes presented an invited talk at the conference "Quasar Hosts" in Tenerife, Sept
1996 entitled "ISO Observations of Quasars and Quasar Hosts". She presented prelimi-
nary results from the ISO data in comparison with host galaxy templates generated by Dr.
McLeod. She also presented colloquia at Wesleyan University and Space Telescope Science
Institute on "The Infrared Continuum of Quasars" including preliminary ISO results.
Ground-based Observing
Analysis of the remainder of the JHK images of our full ISO sample has now been
completed. Optical spectra have been partially reduced and the data organized. The flux
calibration still needs to be completed. We submitted several proposals to the JCMT to
observe the observed-frame mm spectral region just longward of the ISO energy bands in
collaboration with David Hughes and James Dunlop at ROE. The first run on these sources
has been completed but data reduction is not yet complete. We have yet to hear the results
of the latest round of proposals.
Personnel
Dr. McLeod will complete her three-year term as postdoctoral fellow on the ISO project
this summer. Dr. Eric Hooper of Steward Observatory has been hired as her replacement
and will start work in September 1997.
2 TASK B P.I.: J. McDowell
There was no activity on this effort during the first year.
3 TASK C- P.I.: J. Stauffer
As ofthe currentdate,we have onlyreceivedabouthalfofthe observationsthatwere grantedtous
forour program. We do not considerany ofour analysisso fartobe "final"sincethe software
availabletous isstillnot optimizedtodealwiththe known problems with the detectors.However,
we have some results.
We have reduced our ISO observationson 6 Sco-Censtarsat25 and 60 microns,6 IC2602 A starsat
60 microns,and i0 IC2602 G starsat 60 microns. These starsare alsoobservedat90 microns;
those data are not yet reduced. All oftheseobservationswere done as "sparsemaps" in
"staring"mode, meaning a continuousintegrationon the starwith a continuous observationon
a nearby patch ofsky,as opposed tochopping. A few "AOT P22" observations(i.e.,inchopping
mode) were made ofsome targetsbeforewe switchedto "staring"mode; thosedata are alsonot yet
reduced.
Our reductioninvolvedmatching risingor decaying exponentialfunctionsto the raw detector
voltagesin caseswhere the data stream appearstobe affectedbadlyby transients,spikes,etc.
This ismost oftenthe caseforobservationsatthe startofthe "sparsemaps." We solvedfora pre-
dictedasymptoticdetectorresponse as ifforan integrationtime longerthan the 128 secavailable
to us. The asymptoticsolutionsare not hard tofindand appear sensible.We make use ofthis
same techniquetosolveforthe absolutecalibrationfactorin measurements ofthe onboard cali-
brationsource which are alsogenerallyaffectedby seemingly exponential-decay"drifts."
Four ofthe Sco-Cen starshave significant(> 3 sigma) detectionsat25 microns aftersky subtrac-
tion,wellinexcessofexpectedphotosphericfluxes.Our reductionsyielduncertaintiesofabout 1-
sigma = 20 mJy in 128 secon-target/128 secon-skyobservations.The fluxdensitiesinthe sky
"staring"observationsare about 10-30% higherthan COBE observationsat the same ecliptic
latitude,longitude,and solarelongationanglesas our observationswould indicate.This may
be due toa residualsystematiccalibrationerror.
Our 60-micronstaringobservations(also128 secon-target/128 secsky)are presentlyreduced
using nearby sky observationsforfiat-fieldingas well as background subtraction.Only one of
the Sco-Cen starsisdetectedsignificantly(> 3 sigma) inthese CI00 9-pixelarray frames,but
when the 6 starsare coadded,thereisa significant(6sigma)peak inthe centerpixelofthe array
in the flattenedand sky-subtracteddata,and no significantdeviationfrom average in any ofthe
other8 pixels.The sum of6 Sco-Cen starsat60 micronsis1.9Jy (6sigma).Note thatthe same 4
starsdetectedat 25 microns arefound tohave the most significant(although,below 3 sigma)flux
densitiesin pixel5 at 60 microns. The significanceofthe 60-micron measurements can perhaps
be increasedby re-reductionusing,e.g.,a master flat.The calibrationused isfrom measure-
ments ofthe internalsource. However, the averagefluxdensityinthe sky measurements at 60
microns is2x thatin COBE observationsofthe same positions,so our absolutecalibrationseems
quiteuncertainat 60 microns. Itislikelythatwe willbe abletoeventuallyproduce reliabledust
colortemperaturesfrom the 25- and 60-micronmeasurements ofthe 6 Sco-Cen stars.
3
Exploring the Full Range of Quasar /AGN Properties
NAG5-3363: Task C -- John Stauffer
Our similar 60-micron measurements of the 6 IC2602 A stars also show an excess in the center
pixel in the sum of flattened and sky-subtracted frames, in this case 0.6 Jy (3.5 sigma). We do
not have 25-micron measurements of these stars and will not be able to obtain them as there was a
detector problem during the first attempt in summer '96, and the objects are now out of visibility
for the rest of the mission. However, the average luminosity at 60 microns of the A stars in IC
2602 appears to be lower than for the younger Sco-Cen stars.
There is no significant detection at 60 microns in the coaddition of the 10 IC2602 G stars observed
and reduced in the same manner as the A stars; 1-sigma for the center pixel in the coadd is about
0.1 mJy for our present reductions. This sensitivity may be increased by further data reduction.
We have submitted a WIRE GO proposal in order to attempt to improve upon these results, though
we also hope that better processing of the ISO data may allow us to place better constraints on the
IR fluxes of our program objects.
We have not submitted any papers based on our ISO data as yet.
4 TASK D -- P.I.: S. Willner
All observations for this program have now been obtained. The first third of the data set was
observed on 1997 January 27 and the remainder on July 4. The January observations have
been received here and look good, while the July observations have not yet been received.
The plan is to process all the data at one time, probably during a visit to IPAC in
the fall. Analysis should be straightforward once the data are calibrated in physical units.
All required comparison observations are in hand. The budget for this project remains
unchanged.
5 TASK E P.I.: J. Moran
Although water vapor is expected to be very abundant in galaxies, its transitions are impos-
sible to observe fro the earth, except in the partially transparent band longward of 400/_m.
Water vapor has been found in the nuclei of about 15 galaxies, lying in thin rotating gaseous
disks that surround massive (107 M®) central black holes. Microwave emission from this wa-
ter has led to substantial advances in our understanding of these galactic nuclei. However,
unobserved water vapor may lie elsewhere in the nuclei or at different wavelengths. We will
use the ISO satellite to observe water vapor lines at 6#m, 29#m, and 194#m.
The first part of our data was acquired by ISO in March 1997. The post-doctoral fellow
we hired to analyze the data is currently working on its calibration. His appointment will
continue into FY 1998, and the grant will be used to support his activities.
6 TASK F- P.I.: P. Myers
Our ISO program is to observe nine regions of low-mass star formation at mid-infrared
wavelengths to define the positions of the protostars and their associated outflow nebulosity,
for comparison with molecular line maps. The ISO measurements will be used to constrain
the protostellar positions more accurately than is possible form the IRAS satellite, and will
be used to identify circumstellar nebulosity associated with small-scale outflow motions.
The initial first-year analysis of our ISO maps also indicates the presence of multiple sources
where IRAS found only single sources. All of these features are needed to correctly interpret
the kinematic molecular line maps we have made of these regions. Our grant funds will
be used to support collaborative visits with colleagues, to travel to IPAC in Pasadena for
imaging analysis, to travel to meetings (AAS meeting in Washington DC in January 1998 and
Protostars and Planets IV meeting in Santa Barbara, CA in July 1998) to present results,
to purchase an external hard drive to store our data, and to hire a student assistant for each
of two summers to help with data and image analysis.
7 TASK G - P.I.: M. Ashby
At this time, we have received data from a substantial fraction of our proposed observations
from ESTEC. We have photometry data (PHT-03 and PHT-40) in hand for 41 of our galaxies.
We have been fortunate in that a large fraction, some 30 of 45, of our priority 3 targets have
been observed. Observations of an additional 5 galaxies have also been completed and we
expect a delivery of those data shortly. Another 13 observations are pending in the current
ISO schedule. We have chosen not to use PHOT-S as originally proposed since its lower
than expected detector sensitivity made it prohibitive in terms of observing time. We are
focussing instead on the photometry data.
We have examined the majority of the data thus far delivered. We have clear detections
of o our targets thus far in almost all our passbands. At this time, however, we cannot
say that our in-hand data axe completely reduced. We are still gaining experience with the
reduction techniques, particularly with methods for carefully removing retransient signals
from the data in a way that doesn't introduce unwanted systematic errors. But as we
come to understand the calibration techniques (and the data reduction software provided by
ESTEC continues to improve) we expect to resolve these issues. Our intention is to measure
the mid-IR SEDs for all our sample galaxies. A plot is attached showing SEDs for some of
our sample, with the caveat that the fluxes should be regarded as strictly preliminary.
We have not yet submitted any papers based on our ISO dataset.
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ISO Key Project: Exploring the Full Range of Quasar/AGN Properties

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