A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Hubble
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Daily #4055



 
 
Thread Tools Display Modes
  #1  
Old February 22nd 06, 04:20 PM posted to sci.astro.hubble
external usenet poster
 
Posts: n/a
Default Daily #4055

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4055

PERIOD COVERED: UT February 21, 2006 (DOY 052)

OBSERVATIONS SCHEDULED

ACS/HRC 10707

First Mass Measurement of a Planet Found By Microlensing

We will use ACS to determine the mass of the extra-solar planet found
in the ongoing microlensing event OGLE-2005-BLG-071. This source will
be imaged in V {F555W} and I {F814W} at two epochs, one "very soon"
while the event is still significantly magnified, and the other after
5 months when it has returned to baseline. If the centroid does not
move, this will demonstrate that the "blended light" detected in the
event is "perfectly aligned" {within 15 mas, 1 sigma} with the source,
and so is almost certainly the lens. V and I photometry will then
permit an estimate of its mass and distance. Since the planet-star
mass ratio is already known to be 0.007, this will yield a planet
mass. Even if the HST images show that the blended light is not
aligned with the source {and so is not from the lens}, the HST
observations will still strongly constrain the mass by helping to
measure the "microlens parallax", which when combined with the
"angular Einstein radius", determines the mass. Thus, the observations
have a very high probability of success. The observations are
time-critical because the first one must be taken while the event is
still in progress.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

ACS/WFC 10543

Microlensing in M87 and the Virgo Cluster

Resolving the nature of dark matter is an urgent problem. The results
of the MACHO survey of the Milky Way dark halo toward the LMC indicate
that a significant fraction of the halo consists of stellar mass
objects. The VATT/Columbia survey of M31 finds a similar lens fraction
in the M31 dark halo. We propose a series of observations with ACS
that will provide the most thorough search for microlensing toward
M87, the central elliptical galaxy of the Virgo cluster. This program
is optimized for lenses in the mass range from 0.01 to 1.0 solar
masses. By comparing with archival data, we can detect lenses as
massive as 100 solar masses, such as the remnants of the first stars.
These observations will have at least 15 times more sensitivity to
microlensing than any previous survey, e.g. using WFPC2. This is due
to the factor of 2 larger area, factor of more than 4 more sensitivity
in the I-band, superior pixel scale and longer baseline of
observations. Based on the halo microlensing results in the Milky Way
and M31, we might expect that galaxy collisions and stripping would
populate the overall cluster halo with a large number of stellar mass
objects. This program would determine definitively if such objects
compose the cluster dark matter at the level seen in the Milky Way. A
negative result would indicate that such objects do not populate the
intracluster medium, and may indicate that galaxy harassment is not as
vigorous as expected. We can measure the level of events due to the
M87 halo: this would be the best exploration to date of such a lens
population in an elliptical galaxy. Star-star lensing should also be
detectable. About 20 erupting classical novae will be seen, allowing
to determine the definitive nova rate for this giant elliptical
galaxy. We will determine if our recent HST detection of an M87
globular cluster nova was a fluke, or indicative of a 100x higher rate
of incidence of cataclysmic variables and nova eruptions in globulars
than previously believed. We will examine the populations of variable
stars, and will be able to cleanly separate them from microlensing.

ACS/WFC 10596

AGNs with Intermediate-mass Black Holes: A Test of the Black
Hole-Bulge Paradigm

The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9
solar mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {10^4-10^6 solar masses}, if they exist,
may offer important clues to the nature of the seeds of supermassive
black holes. In a first systematic search using the Sloan Digital Sky
Survey, we have recently discovered 19 Type 1 AGNs with candidate
intermediate-mass black holes that reside in low-luminosity,
presumably late-type host galaxies. Follow-up observations with Keck
indicate that these objects obey the low-mass extension of the
well-known correlation between black hole mass and bulge stellar
velocity dispersion. However, very little is known about the host
galaxies themselves, including the crucial question of whether they
have bulges or not. We propose to obtain ACS/WFC images of this unique
sample of AGNs in order to investigate the detailed structural
properties of the host galaxies. We are particularly keen to determine
whether the hosts contain bulges, and if so, where they lie on the
fundamental plane of spheroids compared to the bulges of supermassive
black holes. We will also be able to measure an accurate optical
luminosity for the AGN, which is an essential ingredient to improve
the current mass estimates.

ACS/WFC 10710

Hubble Heritage Observations of ESO 325-G004

The Hubble Heritage team will use a single pointing of ACS WFC to
obtain F475W and F555W images as part of a public release image.

WFPC2 10745

WFPC2 CYCLE 14 INTERNAL MONITOR

This calibration proposal is the Cycle 14 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{both gain 7 and gain 15 -- to test stability of gains and bias
levels}, a test for quantum efficiency in the CCDs, and a monitor for
possible buildup of contaminants on the CCD windows. These also
provide raw data for generating annual super-bias reference files for
the calibration pipeline.

WFPC2 10778

WFPC2 WF4 Supplemental Darks

An anomaly has been found in images from the WF4 CCD in WFPC2. The WF4
CCD bias level appears to have become unstable, resulting in sporadic
images with either low or zero bias level. The severity and frequency
of the problem is rapidly increasing, and it is possible that WF4 will
soon become unusable if no work-around is found. The other three CCDs
{PC1, WF2, and WF3} appear to be unaffected and continue to operate
properly. These darks are to supplement those in program 10748 to
ensure sufficient dark frames for routine calibration. As the WF4
anomaly grows worse, we are beginning to see episodes where too many
darks are corrupted and are unusable.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

10142 - GSAcq(1,2,2) failed to (M2G) due to search radius limit
exceeded on FGS-1 @ 052/1259z

The GSAcq(1,2,2) scheduled at 052/12:59:47 - 13:07:52 failed due to
search radius limit exceeded on FGS-1. 486 ESB "a05" (search radius
limit exceeded) was received at 052/12:50:26. Pre-acquisition OBADs
both suceeded. The 2nd OBAD at 052/12:48:56 had attitude correction
total (RSS) value of 25.22 arcseconds.

10143 - GSAcq(1,2,2) failed to (T2G) due to search radius limit
exceeded on FGS-2 @ 052/1906z

The GSAcq(1,2,2) failed to (T2G) due to search radius limit exceeded
on FGS-2. 486 ESB "a05" (search radius limit exceeded) was received at
052/19:11:54. Also (3x) ESB 1805 (T2G_MOVING_TARGET_DETECTED) was
received at 052/19:12:17. Pre-acquisition OBADs both suceeded; the
GCHALC09 indicator had value 3 for two "successes". The 2nd OBAD at
052/19:02:18 had attitude correction total (RSS) value of 236.25
arcseconds.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 07 05 052/1259z
(HSTAR 10142)
052/1906z
(HSTAR 10143)
FGS REacq 08 08
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
OhOh, Say, Can You See? Ed Conrad Amateur Astronomy 8 January 27th 06 09:41 PM
Judge Jones Has Been Reading the Wrong Books -- Intelligent Design vs. Evolution... Ed Conrad Amateur Astronomy 0 December 22nd 05 10:38 AM
BEST CHRISTMAS PRESENT OF THEM ALL . . . Ed Conrad Amateur Astronomy 10 December 21st 05 02:55 PM
THE BEST CHRISTMAS PRESENT OF ALL Ed Conrad Astronomy Misc 2 December 20th 05 03:31 AM
Ed Conrad's NEW Letter to Prof. Michael Behe Ed Conrad Astronomy Misc 0 June 21st 05 10:50 AM


All times are GMT +1. The time now is 10:13 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.