HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      # 4525

PERIOD COVERED: UT January 011, 2008 (DOY 011)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 DARKs. 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

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

passages leave different imprints on the NICMOS detectors.

WFPC2 11339

A deep observation of NGC4261: understanding its unique X-ray source

population, gas morphology, and jet properties

The nearby early-type galaxy NGC4261 reveals strikingly asymmetric

distributions of X-ray sources as seen with Chandra, and globular

clusters (GC) as seen in the optical band. To address the link between

these populations based on their spatial correlation, luminosity

function and spectral properties, and to investigate the possibility

that this effect is due to the galaxy's merger history, we propose a

100ksec Chandra ACIS-S3 exposure, which will detect X-ray sources down

to typical LMXB luminosities (Lx~5E37 erg/s), and HST-WFPC2 observations

to obtain a deep census of the GC population over the whole galaxy.

These data will also allow a detailed study of its complex gaseous

component, and provide information on the unique two-sided X-ray jet.

WFPC2 11327

Red leaks

The aim of this program is to measure the red leaks in the 8 WFPC2 UV???

filters (F122M, F300W, F255W, F218W, F185W, F170W, F160BW, F122M). We

will use red crossing filters to isolate and directly measure the leaks.

No observations of this kind have ever been performed with WFPC2 to

check the red leaks in the UV filters, most of them being extensively

used by GO/GTO programs. A previous calibration program has only imaged

spectrophotometric standard stars with UV filters (no filter crossing)

thus the red leak is hard to measure using this data. The throughput

curves for some of the UV filters (F300W, F255W, F218W, F185W) in

synphot have incomplete information, some of them have gaps in the

measurements as wide as 3000A.

ACS/SBC 11225

The Wavelength Dependence of Accretion Disk Structure

We can now routinely measure the size of quasar accretion disks using

gravitational microlensing of lensed quasars. The next step to testing

accretion disk models is to measure the size of accretion disks as a

function of wavelength, particularly at the UV and X-ray wavelengths

that should probe the inner, strong gravity regime. Here we focus on two

four- image quasar lenses that already have optical {R band} and X-ray

size measurements using microlensing. We will combine the HST

observations with ground-based monitoring to measure the disk size as a

function of wavelength from the near-IR to the UV. We require HST to

measure the image flux ratios in the ultraviolet continuum near the

Lyman limit of the quasars. The selected targets have estimated black

hole masses that differ by an order of magnitude, and we should find

wavelength scalings for the two systems that are very different because

the Blue/UV wavelengths should correspond to parts of the disk near the

inner edge for the high mass system but not in the low mass system. The

results will be modeled using a combination of simple thin disk models

and complete relativistic disk models. While requiring only 18 orbits,

success for one system requires observations in both Cycles 16 and 17.

WFPC2 11217

The Light Echoes around V838 Monocerotis

V838 Monocerotis, which burst upon the astronomical scene in early 2002,

is a completely unanticipated new object. It underwent a large-amplitude

and very luminous outburst, during which its spectrum remained that of

an extremely cool supergiant. A rapidly evolving set of light echoes

around V838 Mon was discovered soon after the outburst, and quickly

became the most spectacular display of the phenomenon ever seen. These

light echoes provide the means to accomplish three unique types of

measurements based on continued HST imaging during the event: {1} Study

effects of MHD turbulence at high resolution and in 3 dimensions; {2}

Construct the first unambiguous and fully 3-D map of a circumstellar

dust envelope in the Milky Way; {3} Study dust physics in a unique

setting where the spectrum and light curve of the illumination, and the

scattering angle, are unambiguously known. We have also used our HST

data to determine the distance to V838 Mon through direct geometric

techniques. Because of the extreme rarity of light echoes, this is

almost certainly the only opportunity to achieve such results during the

lifetime of HST. We propose two visits during Cycle 16, in order to

continue the mapping of the circumstellar dust and to accomplish the

other goals listed above.

FGS 11213

Distances to Eclipsing M Dwarf Binaries

We propose HST FGS observations to measure accurate distances of 5

nearby M dwarf eclipsing binary systems, from which model-independent

luminosities can be calculated. These objects have either poor or no

existing parallax measurements. FGS parallax determinations for these

systems, with their existing dynamic masses determined to better than

0.5%, would serve as model-independent anchor points for the low-mass

end of the mass-luminosity diagram.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is

seriously incomplete for systems in the period range from years to

millennia because the radial velocity variations are too small and the

angular separations too close for easy detection. Here we propose to

discover binaries in this observational gap through a Faint Guidance

Sensor SNAP survey of relatively bright targets listed in the Galactic O

Star Catalog. Our primary goal is to determine the binary frequency

among those in the cluster/association, field, and runaway groups. The

results will help us assess the role of binaries in massive star

formation and in the processes that lead to the ejection of massive

stars from their natal clusters. The program will also lead to the

identification of new, close binaries that will be targets of long term

spectroscopic and high angular resolution observations to determine

their masses and distances. The results will also be important for the

interpretation of the spectra of suspected and newly identified binary

and multiple systems.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That

measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a

useful result, judged by the over ten refereed citations each year

since. It is, however, unsatisfactory to have the direct,

parallax-based, distance scale of Population II variables based on a

single star. We propose, therefore, to obtain the parallaxes of four

additional RR Lyrae stars and two Population II Cepheids, or W Vir

stars. The Population II Cepheids lie with the RR Lyrae stars on a

common K-band Period- Luminosity relation. Using these parallaxes to

inform that relationship, we anticipate a zero- point error of 0.04

magnitude. This result should greatly strengthen confidence in the

Population II distance scale and increase our understanding of RR Lyrae

star and Pop II Cepheid astrophysics.

WFPC2/NIC3 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.

NIC2 11142

Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3

We aim to determine physical properties of IR luminous galaxies at

0.3<z<2.7 by requesting coordinated HST/NIC2 and MIPS 70um observations

of a unique, 24um flux-limited sample with complete Spitzer mid-IR

spectroscopy. The 150 sources investigated in this program have S{24um}

> 0.8mJy and their mid-IR spectra have already provided the majority

targets with spectroscopic redshifts {0.3<z<2.7}. The proposed

150~orbits of NIC2 and 66~hours of MIPS 70um will provide the physical

measurements of the light distribution at the rest-frame ~8000A and

better estimates of the bolometric luminosity. Combining these

parameters together with the rich suite of spectral diagnostics from the

mid-IR spectra, we will {1} measure how common mergers are among LIRGs

and ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers

of z>1 ULIRGs, as in the local Universe. {2} study the co-evolution of

star formation and blackhole accretion by investigating the relations

between the fraction of starburst/AGN measured from mid-IR spectra vs.

HST morphologies, L{bol} and z. {3} obtain the current best estimates of

the far-IR emission, thus L{bol} for this sample, and establish if the

relative contribution of mid-to-far IR dust emission is correlated with

morphology {resolved vs. unresolved}.

WFPC2 11127

Mapping the nebula surrounding the enigmatic X-ray source at the center

of the Vela Jr SNR

A compact X-ray source, showing nothing but steady unpulsed thermal

emission, lies close to the center of the young and nearby supernova

remnant dubbed "Vela Jr". It is a typical member of a class of enigmatic

sources, supposed to be the youngest members of the radio-quiet neutron

star family. Quite surprisingly, we discovered in ground-based optical

observations a small Halpha nebula spatially coincident with the X-ray

source. Such a nebula potentially carries very important information on

the nature of the X-ray source, which remains elusive in spite of large

observational efforts. We propose to use the WFPC2 to collect high

resolution Halpha images of the nebula in order to resolve its

structure, to understand its nature, and to identify its connection with

the X-ray source. Addressing all these points will also have important

implications for our interpretation of the compact X-ray source and on

of other objects of the same class.

NIC3 11107

Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy

Formation in the Early Universe

We have used the ultraviolet all-sky imaging survey currently being

conducted by the Galaxy Evolution Explorer {GALEX} to identify for the

first time a rare population of low-redshift starbursts with properties

remarkably similar to high-redshift Lyman Break Galaxies {LBGs}. These

"compact UV luminous galaxies" {UVLGs} resemble LBGs in terms of size,

SFR, surface brightness, mass, metallicity, kinematics, dust, and color.

The UVLG sample offers the unique opportunity of investigating some very

important properties of LBGs that have remained virtually inaccessible

at high redshift: their morphology and the mechanism that drives their

star formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS

in order to 1} characterize their morphology and look for signs of

interactions and mergers, and 2} probe their star formation histories

over a variety of timescales. The images show a striking trend of

small-scale mergers turning large amounts of gas into vigorous

starbursts {a process referred to as dissipational or "wet" merging}.

Here, we propose to complete our sample of 31 LBG analogs using the

ACS/SBC F150LP {FUV} and WFPC2 F606W {R} filters in order to create a

statistical sample to study the mechanism that triggers star formation

in UVLGs and its implications for the nature of LBGs. Specifically, we

will 1} study the trend between galaxy merging and SFR in UVLGs, 2}

artificially redshift the FUV images to z=1-4 and compare morphologies

with those in similarly sized samples of LBGs at the same rest-frame

wavelengths in e.g. GOODS, UDF, and COSMOS, 3} determine the presence

and morphology of significant stellar mass in "pre-burst" stars, and 4}

study their immediate environment. Together with our Spitzer

{IRAC+MIPS}, GALEX, SDSS and radio data, the HST observations will form

a unique union of data that may for the first time shed light on how the

earliest major episodes of star formation in high redshift galaxies came

about. This proposal was adapted from an ACS HRC+WFC proposal to meet

the new Cycle 16 observing constraints, and can be carried out using the

ACS/SBC and WFPC2 without compromising our original science goals.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive

Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured

Universe

(uses ACS/SBC and WFPC2)

Deep near-infrared imaging provides the only avenue towards

understanding a host of astrophysical problems, including: finding

galaxies and AGN at z > 7, the evolution of the most massive galaxies,

the triggering of star formation in dusty galaxies, and revealing

properties of obscured AGN. As such, we propose to observe 60 selected

areas of the GOODS North and South fields with NICMOS Camera 3 in the

F160W band pointed at known massive M > 10^11 M_0 galaxies at z > 2

discovered through deep Spitzer imaging. The depth we will reach {26.5

AB at 5 sigma} in H_160 allows us to study the internal properties of

these galaxies, including their sizes and morphologies, and to

understand how scaling relations such as the Kormendy relationship

evolved. Although NIC3 is out of focus and undersampled, it is currently

our best opportunity to study these galaxies, while also sampling enough

area to perform a general NIR survey 1/3 the size of an ACS GOODS field.

These data will be a significant resource, invaluable for many other

science goals, including discovering high redshift galaxies at z > 7,

the evolution of galaxies onto the Hubble sequence, as well as examining

obscured AGN and dusty star formation at z > 1.5. The GOODS fields are

the natural location for HST to perform a deep NICMOS imaging program,

as extensive data from space and ground based observatories such as

Chandra, GALEX, Spitzer, NOAO, Keck, Subaru, VLT, JCMT, and the VLA are

currently available for these regions. Deep high-resolution

near-infrared observations are the one missing ingredient to this

survey, filling in an important gap to create the deepest, largest, and

most uniform data set for studying the faint and distant universe. The

importance of these images will increase with time as new facilities

come on line, most notably WFC3 and ALMA, and for the planning of future

JWST observations.

NIC1 11057

Cycle 15 NICMOS dark current, shading profile, and read noise monitoring

program

The purpose of this proposal is to monitor the dark current, read noise,

and shading profile for all three NICMOS detectors throughout the

duration of Cycle 15. This proposal is a slightly modified version of

proposal 10380 of cycle 13 and 9993 of cycle12 and is the same as Cycle

14. that we cut down some exposure time to make the observation fit

within 24 orbits.

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly

Monitor

Intflat observations will be taken to provide a linearity check: the

linearity test consists of a series of intflats in F555W, in each gain

and each shutter. A combination of intflats, visflats, and earthflats

will be used to check the repeatability of filter wheel motions.

{Intflat sequences tied to decons, visits 1-18 in prop 10363, have been

moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note:

long-exposure WFPC2 intflats must be scheduled during ACS anneals to

prevent stray light from the WFPC2 lamps from contaminating long ACS

external exposures.

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for

supernovae {SNe}, most notably our Lick Observatory Supernova Search

{LOSS}, have found hundreds of SNe, many of them in quite nearby

galaxies {cz < 4000 km/s}. Most of the objects were discovered before

maximum brightness, and have follow-up photometry and spectroscopy; they

include some of the best-studied SNe to date. We propose to conduct a

snapshot imaging survey of the sites of some of these nearby objects, to

obtain late-time photometry that {through the shape of the light and

color curves} will help reveal the origin of their lingering energy. The

images will also provide high-resolution information on the local

environments of SNe that are far superior to what we can procure from

the ground. For example, we will obtain color-color and color- magnitude

diagrams of stars in these SN sites, to determine the SN progenitor

masses and constraints on the reddening. Recovery of the SNe in the new

HST images will also allow us to actually pinpoint their progenitor

stars in cases where pre- explosion images exist in the HST archive.

This proposal is an extension of our successful Cycle 13 snapshot survey

with ACS. It is complementary to our Cycle 15 archival proposal, which

is a continuation of our long- standing program to use existing HST

images to glean information about SN environments.

NIC3 10874

Search for Extremely Faint z>7 Galaxy Population with Cosmic Lenses

Deep UDF/NICMOS observations find a significant decrease in the number

of galaxy candidates between redshift z=6 and 7, but the sample at z>7

is too small to draw conclusions. From our observations of 15 clusters

we have found a number of bright z-dropouts, aided by the lensing

amplification. We propose deep NICMOS observations of the best cases of

cluster centers where a rare combination of a significant lensing effect

and the richness in z-band dropouts in background may dramatically

increase the discovery rate. The NICMOS images will reach an

unprecedented depth of AB~27.8, or AB~30 in nonlensed intrinsic

magnitude, and may find many faint {~0.05L*} galaxies at z=7-10, at a

level that the UDF reaches for z~6 objects. We produce precision mass

distribution maps from weak-lensing models, which enable us to derive

the candidates' intrinsic magnitudes and their luminosity function. The

knowledge of such faint galaxy population at z>7 will facilitate the

models of the IGM reionization and future JWST planning.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

11141 - REAcq (1,2,1) failed to RGA Hold

           At 014/03:17:03, REAcq (1,2,1) scheduled from 03:13:33 - 03:20:34 failed

           to RGA Hold. Received both QF2STOPF & QSTOP flags. Pre-acquisition OBAD

           #1 RSS = 1075.68 a-s. Pre-acquisition OBAD #2 RSS = 12.67 a-s.

           Post-acquisition OBAD MAP was not scheduled. FGS 2 achieved finelock at

           03:16:51 but, lost it at 03:17:01.

11142 - REAcq (1,2,1) resulted in fine lock back-up (1,0,1)

           REAcq (1,2,1) scheduled from 014/08:52:14 - 08:59:29 resulted in fine

           lock back-up (1,0,1) using FGS 1. Received QF2STOPF & QSTOP flags.

           Pre-acquisition OBAD #1 data unavailable due to a scheduled loss of

           signal. Pre-acquisition OBAD #2 RSS = 8.37 a-s. Post-acquisition OBAD

           MAP RSS = 9.41 a-s.

COMPLETED OPS REQUEST:

18170-1 - Uplink new FGS Alignment and Calibration tables

COMPLETED OPS NOTES: (None)

                      SCHEDULED      SUCCESSFUL

FGS GSacq               19                 19                  

FGS REacq               20                 19          

OBAD with Maneuver 78                 78               

SIGNIFICANT EVENTS:

OPS Flash Report:

The FGS Alignment and Calibration table uplink

activity scheduled for 014/00:15 was successfully completed. The guide

star acquisition at 01:37 was nominal.