DAILY REPORT #3906

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #3906

PERIOD COVERED: UT July 20, 2005 (DOY 201)

OBSERVATIONS SCHEDULED

ACS/HRC 10606

Ultraviolet Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain ACS NUV images of 3CR sources with z0.3 as a major enhancement
to an already superb dataset. We aim to reveal dust in galaxies,
regions of star and star cluster formation frequently associated with
dust and establish the physical characteristics of the dust itself. We
will measure frequency and spectral energy distributions of point-like
nuclei, seek spectral turnovers in known synchrotron jets and find new
jets. We will strongly test unified AGN schemes and merge these data
with existing X-ray to radio observations for significant numbers of
both FR-I and FR-II sources. The resulting database will be an
incredibly valuable resource to the astronomical community for years
to come.

ACS/HRC/WFC 10389

ACS CCDs daily monitor - Cycle 13 - Part 2

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This program will be
for the entire lifetime of ACS.

ACS/HRC/WFC 10411

Catching optical emission from the first discovered double-pulsar
system: J0737-3039

This proposal is aimed to detect optical emission from one of the most
intriguing astronomical object ever found in the sky: the newly
discovered binary system harbouring two pulsar {PSR J0737-3039A and
PSR J0737-3039B}. This is the first double- pulsar system ever
detected {Burgay et al. 2003; Lyne et al. 2004} and it provides a
wonderful laboratory for the study of relativistic gravity and
gravitational radiation. Moreover, for the first time, it offers the
opportunity to probe the magnetosphere and the local environment of a
neutron star. There is indeed evidence of strong interactions between
the energy released by one pulsar and the magnetosphere of the other.
Our team is now carrying out a multi-wavelength project to understand
the nature of the occurring interactions and the energy budget of the
system. In particular, while radio observations will continue to
survey the object, X-ray observations with Chandra have been already
allocated. Here we ask for deep ACS-HR observations to catch the
optical emission from the system. These observations will firstly
estimate the optical nonthermal flux, and, once combined with radio
and X-ray fluxes, will give us unique insights into the physics of the
relativistic wind interactions within the system.

ACS/WFC 10407

When did M31's disk form?

The recent discovery of THIN disk globular clusters in M31 provides a
unique opportunity to determine the age of M31's disk. The globular
cluster kinematics imply that the disk has not been significantly
heated or destroyed by a merger since they were formed. Thus the
cluster ages provide a lower limit to the disk age. This limit will
complement the high-redshift data, where few disk galaxies are
currently known because of their relatively low surface brighness. We
propose to obtain BV ACS imaging of seven disk clusters to below the
level of the horizontal branch {HB} to determine the distribution of
evolved stars in the color-magnitude diagram. The contribution of
evolved stars, particularly blue HB stars, is crucial to estimating
the age of the globular cluster from both color-magnitude diagrams and
the high S/N integrated spectra which we will obtain from the ground.

ACS/WFC/WFPC2 10394

Deep imaging of newly discovered globular clusters in the outer halo
of M31

Globular clusters {GCs} are fossil relics with which we can
investigate the processes of galaxy formation and growth. We have
recently discovered a sample of GCs, as part of a very wide area CCD
survey of M31. These clusters span a range in projected galactocentric
distance of 20 - 80 kpc, more than double the radii of the previous
most remote known GC. Here we apply for deep ACS images of 13 GCs,
which will allow us to study their stellar populations, line-of-sight
distances and structural parameters. These will be used to: a}
Investigate the merger history of M31, through an examination of
variations in the RGB and HB morphologies, particularly to obtain
metallicities and check for the presence of any second parameter
effect in the HB. d} Determine, in conjuction with ground-based
spectroscopy, the dynamical mass of M31 at large radius, providing a
direct probe of the mass distribution of its dark halo.

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 09 09
FGS Reacq 07 07
FHST Update 10 10

SIGNIFICANT EVENTS: (None)