HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT    # 4556

PERIOD COVERED: UT February 27, 2008 (DOY 058)

OBSERVATIONS SCHEDULED

FGS 11298

Calibrating Cosmological Chronometers: White Dwarf Masses

We propose to use HST/FGS1R to determine White Dwarf {WD} masses. The

unmatched resolving power of HST/FGS1R will be utilized to follow up

four selected WD binary pairs. This high precision obtained with

HST/FGS1R simply cannot be equaled by any ground based technique. This

proposed effort complements that done by CoI Nelan in which a sample of

WDs is being observed with HST/FGS1R. This proposal will dramatically

increase the number of WDs for which dynamical mass measurements are

possible, enabling a better calibration of the WD mass-radius relation,

cooling curves, initial to final mass relations, and ultimately giving

important clues to the star formation history of our Galaxy and the age

of its disk as well as in other galaxies. {This project is part of

Subasavage's PhD thesis work at Georgia State University.}

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of

NICMOS. Dark frames will be obtained immediately upon exiting the SAA

contour 23, and every time a NICMOS exposure is scheduled within 50

minutes of coming out of the SAA. The darks will be obtained in parallel

in all three NICMOS Cameras. The POST-SAA darks will be non-standard

reference files available to users with a USEAFTER date/time mark. The

keyword 'USEAFTER=date/time' will also be added to the header of each

POST-SAA DARK frame. The keyword must be populated with the time, in

addition to the date, because HST crosses the SAA ~8 times per day so

each POST-SAA DARK will need to have the appropriate time specified, for

users to identify the ones they need. Both the raw and processed images

will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS

science/calibration observations started within 50 minutes of leaving an

SAA will need such maps to remove the CR persistence from the science i

mages. Each observation will need its own CRMAP, as different SAA

passages leave different imprints on the NICMOS detectors.

NIC2 11135

Extreme makeovers: Tracing the transformation of massive galaxies at

z~2.5

To obtain a full spectroscopic census of the universe at z~2.5 we have

conducted a near-infrared spectroscopic survey for K-selected galaxies.

We found that, in contrast to the local universe, massive high-redshift

galaxies span a wide range of properties, varying from (dusty) star

burst to "red and dead" galaxies. This may imply that massive galaxies

transform from star-forming to quiescent galaxies in the targeted

redshift range. To understand whether the 9 quiescent galaxies in our

sample are the progenitors of local elliptical, we are observing them in

the current cycle with NIC2. For cycle 16 we propose to complete our

sample of massive z~2.5 galaxies and image the remaining 10 galaxies,

which all have emission lines. Based on emission-line diagnostics, 6 of

these galaxies are identified as star-forming objects and 4 harbor an

active galactic nucleus. The goals are to 1) determine whether star

formation in massive z~2.5 galaxies takes place in disks or is triggered

by merger activity, 2) derive the contribution of AGNs to the rest-frame

optical emission, and 3) test whether the morphologies are consistent

with the idea that the star-forming galaxies, AGNs, and quiescent

galaxies represent subsequent phases of an evolutionary sequence. The

combination of both programs will provide the first morphological study

of a spectroscopically confirmed massive galaxy sample at z~2.5.

NIC2 11143

NICMOS imaging of submillimeter galaxies with CO and PAH redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter

galaxies {SMGs} whose optical redshifts have been confirmed by the

detection of millimeter CO and/or mid- infrared PAH emission. With the

4000A break falling within/between the two imaging filters, we will be

able to study these sources' spatially resolved stellar populations

{modulo extinction} in the rest-frame optical. SMGs' large luminosities

appear to be due largely to merger-triggered starbursts; high-resolution

NICMOS imaging will help us understand the stellar masses, mass ratios,

and other properties of the merger progenitors, valuable information in

the effort to model the mass assembly history of the universe.

NIC2 11219

Active Galactic Nuclei in nearby galaxies: a new view of the origin of

the radio-loud radio-quiet dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type

galaxies {drawn from a complete radio selected sample} we have found

evidence that the radio-loud/radio-quiet dichotomy is directly connected

to the structure of the inner regions of their host galaxies in the

following sense: [1] Radio-loud AGN are associated with galaxies with

shallow cores in their light profiles [2] Radio-quiet AGN are only

hosted by galaxies with steep cusps. Since the brightness profile is

determined by the galaxy's evolution, through its merger history, our

results suggest that the same process sets the AGN flavour. This

provides us with a novel tool to explore the co-evolution of galaxies

and supermassive black holes, and it opens a new path to understand the

origin of the radio-loud/radio-quiet AGN dichotomy. Currently our

analysis is statistically incomplete as the brightness profile is not

available for 82 of the 116 targets. Most galaxies were not observed

with HST, while in some cases the study is obstructed by the presence of

dust features. We here propose to perform an infrared NICMOS snapshot

survey of these 82 galaxies. This will enable us to i} test the reality

of the dichotomic behaviour in a substantially larger sample; ii} extend

the comparison between radio-loud and radio-quiet AGN to a larger range

of luminosities.

NIC3 11120

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic

Center

The Galactic center (GC) is a unique site for a detailed study of a

multitude of complex astrophysical phenomena, which may be common to

nuclear regions of many galaxies. Observable at resolutions

unapproachable in other galaxies, the GC provides an unparalleled

opportunity to improve our understanding of the interrelationships of

massive stars, young stellar clusters, warm and hot ionized gases,

molecular clouds, large scale magnetic fields, and black holes. We

propose the first large-scale hydrogen Paschen alpha line survey of the

GC using NICMOS on the Hubble Space Telescope. This survey will lead to

a high resolution and high sensitivity map of the Paschen alpha line

emission in addition to a map of foreground extinction, made by

comparing Paschen alpha to radio emission. This survey of the inner 75

pc of the Galaxy will provide an unprecedented and complete search for

sites of massive star formation. In particular, we will be able to (1)

uncover the distribution of young massive stars in this region, (2)

locate the surfaces of adjacent molecular clouds, (3) determine

important physical parameters of the ionized gas, (4) identify compact

and ultra-compact HII regions throughout the GC. When combined with

existing Chandra and Spitzer surveys as well as a wealth of other

multi-wavelength observations, the results will allow us to address such

questions as where and how massive stars form, how stellar clusters are

disrupted, how massive stars shape and heat the surrounding medium, and

how various phases of this medium are interspersed.

WFPC2 11030

WFPC2 WF4 Temperature Reduction #3

In the fall of 2005, a serious anomaly was found in images from the WF4

CCD in WFPC2. The WF4 CCD bias level appeared to have become unstable,

resulting in sporadic images with either low or zero bias level. The

severity and frequency of the problem was rapidly increasing, making it

possible that WF4 would soon become unusable if no work-around were

found. Examination of bias levels during periods with frequent WFPC2

images showed low and zero bias episodes every 4 to 6 hours. This

periodicity is driven by cycling of the WFPC2 Replacement Heater, with

the bias anomalies occurring at the temperature peaks. The other three

CCDs {PC1, WF2, and WF3} appear to be unaffected and continue to operate

properly. Lowering the Replacement Heater temperature set points by a

few degrees C effectively eliminates the WF4 anomaly. On 9 January 2006,

the upper set point of the WFPC2 Replacement Heater was reduced from

14.9C to 12.2C. On 20 February 2006, the upper set point was reduced

from 12.2C to 11.3C, and the lower set point was reduced from 10.9C to

10.0C. These changes restored the WF4 CCD bias level; however, the bias

level has begun to trend downwards again, mimicking its behavior in late

2004 and early 2005. A third temperature reduction is planned for March

2007. We will reduce the upper set point of the heater from 11.3C to

10.4C and the lower set point from 10.0C to 9.1C. The observations

described in this proposal will test the performance of WFPC2 before and

after this temperature reduction. Additional temperature reductions may

be needed in the future, depending on the performance of WF4. Orbits:

internal 26, external 1

WFPC2 11222

Direct Detection and Mapping of Star Forming Regions in Nearby, Luminous

Quasars

We propose to carry out narrow-band emission line imaging observations

of 8 quasars at z=0.05-0.15 with the WFPC2 ramp filters and with the

NICMOS narrow-band filters. We will obtain images in the [O II], [O

III], H-beta, and Pa-alpha emission line bands to carry out a series of

diagnostic tests aimed at detecting and mapping out star-forming regions

in the quasar host galaxies. This direct detection of star-forming

regions will confirm indirect indications for star formation in quasar

host galaxies. It will provide a crucial test for models of quasar and

galaxy evolution, that predict the co-existence of starbursts and

"monsters" and will solve the puzzle of why different indicators of star

formation give contradictory results. A secondary science goal is to

assess suggested correlations between quasar luminosity and the size of

the narrow-line region.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                               SCHEDULED      SUCCESSFUL

FGS GSacq                      08                 08                  

FGS REacq                      06                  06                 

OBAD with Maneuver       28                  28               

SIGNIFICANT EVENTS:

FLASH REPORT:  

WFPC2 CCD4 replacement heater in-flight temperature adjustment

#5 functionally verified At 058/18:40z, the replacement heaters

were observed turning on when Bay1 fell to 7.22 °C.  About 7

minutes later they were disabled when Bay1 reached 8.44 °C as

expected, functionally verifying the patches.