HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4641

PERIOD COVERED: 5am June 26 - 5am June 27, 2008 (DOY 178/0900z-179/0900z)

OBSERVATIONS SCHEDULED

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 11237

The Origin of the Break in the AGN Luminosity Function

We propose to use NICMOS imaging to measure rest-frame optical

luminosities and morphological properties of a complete sample of faint

AGN host galaxies at redshifts z ~ 1.4. The targets are drawn from the

VLT-VIMOS Deep Survey, and they constitute a sample of the lowest

luminosity type 1 AGN known at z > 1. The spectroscopically estimated

black hole masses are up to an order of magnitude higher than expected

given their nuclear luminosities, implying highly sub-Eddington

accretion rates. This exactly matches the prediction made by recent

theoretical models of AGN evolution, according to which the faint end of

the AGN luminosity function is populated mainly by big black holes that

have already exhausted a good part of their fuel. In this proposal we

want to test further predictions of that hypothesis, by focussing on the

host galaxy properties of our low-luminosity, low- accretion AGN. If the

local ratio between black hole and bulge masses holds at least

approximately at these redshifts, one expects most of these

low-luminosity AGN to reside in fairly big ellipticals with stellar

masses around and above 10^11 solar masses (in contrast to the Seyfert

phenomenon in the local universe). With NICMOS imaging we will find out

whether that is true, implying also a sensitive test for the validity of

the M_BH/M_bulge relation at z ~ 1.4.

WFPC2 11206

At the Cradle of the Milky Way: Formation of the Most Massive Field Disk

Galaxies at z>1

We propose to obtain 2 orbit WFPC2 F814W images of a sample of the 15

most massive galaxies found at $1 < z < 1.3$. These were culled from

over 20,000 Keck spectra collected as part of DEEP and are unique among

high redshift massive galaxy samples in being kinematically selected.

Through a recent HST NICMOS-2 imaging program {GO-10532}, we have

confirmed that these galaxies have regular stellar disks, and their

emission line kinematics are not due to gradients from merging

components. These potentially very young galaxies are likely precursors

to massive local disks, assuming no further merging. The proposed WFPC2

and existing NIC-2 data provide colors, stellar masses, and ages of

bulge and disk subcomponents, to assess whether old stellar bulges and

disks are in place at that time or still being built, and constrain

their formation epochs. Finally, this sample will yield the first

statistically significant results on the $z > 1$ evolution of the

size-velocity-luminosity scaling relations, for massive galaxies at

different wavelengths, and constrain whether this evolution reflects

stellar mass growth, or passive evolution, of either bulge or disk

components.

WFPC2 11235

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies

in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared

selected galaxies exceeds that of optically selected galaxies. These

`luminous infrared galaxies' {LIRGs} are primarily interacting or

merging disk galaxies undergoing enhanced star formation and Active

Galactic Nuclei {AGN} activity, possibly triggered as the objects

transform into massive S0 and elliptical merger remnants. We propose

NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88

L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised

Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}.

This sample is ideal not only in its completeness and sample size, but

also in the proximity and brightness of the galaxies. The superb

sensitivity and resolution of NICMOS NIC2 on HST enables a unique

opportunity to study the detailed structure of the nuclear regions,

where dust obscuration may mask star clusters, AGN and additional nuclei

from optical view, with a resolution significantly higher than possible

with Spitzer IRAC. This survey thus provides a crucial component to our

study of the dynamics and evolution of IR galaxies presently underway

with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88

galaxies. Imaging will be done with the F160W filter {H-band} to examine

as a function of both luminosity and merger stage {i} the luminosity and

distribution of embedded star clusters, {ii} the presence of optically

obscured AGN and nuclei, {iii} the correlation between the distribution

of 1.6 micron emission and the mid- IR emission as detected by Spitzer

IRAC, {iv} the evidence of bars or bridges that may funnel fuel into the

nuclear region, and {v} the ages of star clusters for which photometry

is available via ACS/WFC observations. The NICMOS data, combined with

the HST ACS, Spitzer, and GALEX observations of this sample, will result

in the most comprehensive study of merging and interacting galaxies to

date.

WFPC2/NIC3 11188

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for

reionization of the universe at z>6. However, the models that attempt to

describe the detailed impact of high- redshift galaxies on the

surrounding inter-galactic medium {IGM} are strongly dependent upon

several uncertain parameters. Perhaps the most uncertain is the fraction

of HI-ionizing photons produced by young stars which escape into the

IGM. Most attempts to measure this "escape fraction" {f_esc} have

produced null results. Recently, a small subset of z~3 Lyman Break

Galaxies {LBGs} has been found exhibiting large escape fractions. It

remains unclear however, what differentiates them from other LBGs.

Several models attempt to explain how such a large fraction of ionizing

continuum can escape through the HI and dust in the ISM {eg. "chimneys"

created by SNe winds, globular cluster formation, etc.}, each producing

unique signatures which can be observed with resolved imaging of the

escaping Lyman continuum. We propose a deep, high resolution WFPC2 image

of the ionizing continuum {F336W} and the rest-frame 1500 Angstrom

continuum {F606W} of five of the six known LBGs with large escape

fractions. These LBGs all fit within a single WFPC2 pointing, yielding

high observing efficiency. Additionally, they all have z~3.1 or higher,

the optimal redshift range for probing the Lyman Continuum region with

available WFPC2 filters. These factors make our proposed sample

especially suitable for follow- up. With these data we will discern the

mechanisms responsible for producing large escape fractions, and

therefore gain insight into the process of reionization.

WFPC2/NIC3/ACS/SBC 11144

Building on the Significant NICMOS Investment in GOODS: A Bright,

Wide-Area Search for z>=7 Galaxies

One of the most exciting frontiers in observational cosmology has been

to trace the buildup and evolution of galaxies from very early times.

While hierarchical theory teaches us that the star formation rate in

galaxies likely starts out small and builds up gradually, only recently

has it been possible to see evidence for this observationally through

the evolution of the LF from z~6 to z~3. Establishing that this build up

occurs from even earlier times {z~7-8} has been difficult, however, due

to the small size of current high-redshift z~7-8 samples -- now

numbering in the range of ~4-10 sources. Expanding the size of these

samples is absolutely essential, if we are to push current studies of

galaxy buildup back to even earlier times. Fortunately, we should soon

be able to do so, thanks to ~50 arcmin**2 of deep {26.9 AB mag at 5

sigma} NICMOS 1.6 micron data that will be available over the two ACS

GOODS fields as a result of one recent 180- orbit ACS backup program and

a smaller program. These data will nearly triple the deep near-IR

imaging currently available and represent a significant resource for

finding and characterizing the brightest high-redshift sources -- since

high-redshift candidates can be easily identified in these data from

their red z-H colours. Unfortunately, the red z-H colours of these

candidates are not sufficient to determine that these sources are at

z>=7, and it is important also to have deep photometry at 1.1 microns.

To obtain this crucial information, we propose to follow up each of

these z-H dropouts with NICMOS at 1.1 microns to determine which are at

high redshift and thus significantly expand our sample of luminous, z>=7

galaxies. Since preliminary studies indicate that these candidates occur

in only 30% of the NIC3 fields, our follow-up strategy is ~3 times as

efficient as without this preselection and 9 times as efficient as a

search in a field with no pre-existing data. In total, we expect to

identify ~8 luminous z-dropouts and possibly ~2 z~10 J-dropouts as a

result of this program, more than tripling the number currently known.

The increased sample sizes are important if we are to solidify current

conclusions about galaxy buildup and the evolution of the LF from z~8.

In addition to the high redshift science, these deep 1.1 micron data

would have significant value for many diverse endeavors, including {1}

improving our constraints on the stellar mass density at z~7-10 and {2}

doubling the number of galaxies at z~6 for which we can estimate dust

obscuration.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

11356 - GSAcq (2,0,2) failed to RGA Hold

           At Acquisition of Signal, 178/09:48:55, GSAcq (2,0,2) scheduled from

           178/09:25:51 - 09:31:21 had failed to RGA Hold. This was due to QF2STOPF

           flag on FGS 2. No other ESB messages were noted. OBAD #1 & #2 data is

           unavailable due to loss of signal. OBAD MAP: V1 -12.70, V2 -6.40, V3

           -0.32, RSS 14.22 arc seconds. Awaiting engineering data dump for further

           analysis.

           Possible observations affected: NICMOS Proposal 11235, Observation

           Numbers 171 & 172

11358 - GSACQ(2,1,2) failed, scan step limit exceeded on FGS 2

           GSACQ(2,1,2) at 178/14:24:40 failed due to scan step limit exceeded on

           FGS 2 at 14:28:37. No ESB messages were received, #44 commands did not

           update from their values prior to LOS.

           Observations affected: WFPC 126 to 129, Proposal number 11206

11359 - REacq(1,2,1) failed to RGA Hold

           During LOS REacq(1,2,2) scheduled at 178/2040:03 - 20:47:22 failed to

           RGA hold. At AOS (21:51:08) stop flags QF1STOPF and QSTOP were set for

           FGS 1. Also during LOS we received an ESB 1805 "FHST moving target det".

           Observations affected: NIC 176 Proposal ID#11237

           The REacq(1,2,2) scheduled at 22:15:57 also failed to RGA hold. Stop

           flags QF1STOPF and QSTOP were set for FGS 1.

           OBAD1 showed errors of V1=1261.02, V2=-1096.80, V3=-745.72 and RSS=

           1830.10. OBAD2 showed errors of V1=-9.69, V2=-8.90, V3=15.49.

           Observations affected: NIC 177 Proposal ID#08795 and NIC 178 Proposal

           ID#11237

           REacq(1,2,2) at 23:51:52 also failed with stop flags on FGS 1.

           Observations affected: NIC 179 Proposal ID#08795, NIC 180 Proposal ID#11237

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL 

FGS GSacq               05                  03 

FGS REacq               10                  07 

OBAD with Maneuver 30                  30                                                 

SIGNIFICANT EVENTS: (None)