Status Report

NASA Hubble Space Telescope Daily Report #4216

By SpaceRef Editor
October 11, 2006
Filed under , ,
NASA Hubble Space Telescope Daily Report #4216


– Continuing to collect World Class Science

PERIOD COVERED: UT October 10, 2006 (DOY 283)



CCD Hot Pixel Annealing

Hot pixel annealing will continue to be performed once every 4 weeks. The CCD TECs will be turned off and heaters will be activated to bring the detector temperatures to about +20C. This state will be held for approximately 6 hours, after which the heaters are turned off, the TECs turned on, and the CCDs returned to normal operating condition. To assess the effectiveness of the annealing, a bias and four dark images will be taken before and after the annealing procedure for both WFC and HRC. The HRC darks are taken in parallel with the WFC darks. The charge transfer efficiency {CTE} of the ACS CCD detectors declines as damage due to on-orbit radiation exposure accumulates. This degradation has been closely monitored at regular intervals, because it is likely to determine the useful lifetime of the CCDs. We combine the annealling activity with the charge transfer efficiency monitoring and also merge into the routine dark image collection. To this end, the CTE monitoring exposures have been moved into this proposal . All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} and First Pixel Response {FPR} data will be obtained over a range of signal levels for both the Wide Field Channel {WFC}, and the High Resolution Channel {HRC}.

ACS/WFC 10633

GRB afterglows and host galaxies at very high redshifts

Cosmology is beginning to constrain the nature of the earliest stars and galaxies to form in the universe, but direct observation of galaxies at z>6 remains highly challenging due to their scarcity, intrinsically small size, and high luminosity distance. GRB afterglows, thanks to their extreme luminosities, offer the possibility of circumventing these normal constraints by providing redshifts and spectral information which couldn’t be obtained by direct observation of the hosts themselves. In addition, the association of GRBs with massive stars means that they are a tracer of star formation, and that their hosts are likely responsible for a large proportion of the ionizing radiation during that era. Our collaboration is mounting a campaign to rapidly identify and study candidate very high redshift bursts, bringing to bear a network of 2, 4 and 8m telescopes with nIR instrumentation. The capabilities of Swift to detect faint, distant GRBs, and to report accurate positions for many bursts in near real-time makes our program now feasible. HST is crucial to this endeavour, allowing us {a} to monitor the late time afterglows and hence compare them to lower-z bursts and test the use of GRBs as standard candles; and {b} characterise the basic properties, luminosities, and in some cases morphologies, of the hosts, which is essential to understanding these primordial galaxies and their relationship to other populations.

ACS/WFC 10848

Relating the host galaxies of type-2 quasars to their infrared properties

The obscured quasar population has been found to consist of a wide variety of objects. In this proposal, we wish to study the host galaxies of six z~0.6 type-2 quasars selected via their mid- infrared emission. Infrared spectra and photometry of these objects show that they include both actively star-forming and non-starforming galaxies, and have dust columns to the AGN ranging from moderate to high. We will relate the host galaxy properties to the infrared properties of these type-2 quasars, and to the host galaxies of type-1 quasars of similar redshift and bolometric luminosity. These observations will thus help us to understand how the different types of obscured quasars are related to each other, and to the normal quasar population.

FGS 10912

Trigonometric Calibration of the Distance Scale for Classical Novae

The distance scale for classical novae is important for understanding the stellar physics of their thermonuclear runaways, their contribution to Galactic nucleosynthesis, and their use as extragalactic standard candles. Although it is known that there is a relationship between their absolute magnitudes at maximum light and their subsequent rates of decline–the well-known maximum-magnitude rate-of-decline {MMRD} relation–it is difficult to set the zero-point for the MMRD because of the very uncertain distances of Galactic novae. We propose to measure precise trigonometric parallaxes for the quiescent remnants of the four nearest classical novae. We will use the Fine Guidance Sensors, which are proven to be capable of measuring parallaxes with errors of ~0.2 mas, well below what is possible from the ground.

NIC1 11061

NICMOS Imaging of Grism Spectrophotometric Standards

In this program we will take imaging observations with all 3 cameras with a range of filters of a significant number of stars that are part of the spectroscopic standard star project. These stars will form the fainter reference star backbone for programs as JWST, Sophia, and SNAP. With this program we will: 1. Accurately calibrate relative brightness of standard stars, which can be done more accurately with photometry than with spectroscopy. This has been proven to be vary valuable to straighten out the problems in the spectroscopic data reduction and calibrations so far. 2. Increase the number of stars over a large magnitude range to provide a more accurate cross check of our count rate dependent non-linearity correction 3. Include stars with radically different {very red} spectra to investigate whether the filter curves as measured before flight are still valid by comparing the throughput estimates from these stars to those used for the standard calibration. 4. Repeat a few standard star observations from cycle 7 and post-NCS installation SMOV, to increase the accuracy in the change in sensitivity measurement with just a few observations thanks to the long baseline.

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 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 images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC2 10893

Sweeping Away the Dust: Reliable Dark Energy with an Infrared Hubble Diagram

We propose building a high-z Hubble Diagram using type Ia supernovae observed in the infrared rest-frame J-band. The infrared has a number of exceptional properties. The effect of dust extinction is minimal, reducing a major systematic tha may be biasing dark energy measurements. Also, recent work indicates that type Ia supernovae are true standard candles in the infrared meaning that our Hubble diagram will be resistant to possible evolution in the Phillips relation over cosmic time. High signal-to-noise measurements of 9 type Ia events at z~0.4 will be compared with an independent optical Hubble diagram from the ESSENCE project to test for a shift in the derived dark energy equation of state due to a systematic bias. Because of the bright sky background, H-band photometry of z~0.4 supernovae is not feasible from the ground. Only the superb image quality and dark infrared sky seen by HST makes this test possible. This experiment may also lead to a better, more reliable way of mapping the expansion history of the universe with the Joint Dark Energy Mission.

NIC3 10792

Quasars at Redshift z=6 and Early Star Formation History

We propose to observe four high-redshift quasars {z=6} in the NIR in order to estimate relative Fe/Mg abundances and the central black hole mass. The results of this study will critically constrain models of joint quasar and galaxy formation, early star formation, and the growth of supermassive black holes. Different time scales and yields for alpha-elements {like O or Mg} and for iron result into an iron enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the well-known complexity of the FeII emission line spectrum, the ratio iron/alpha – element is a potentially useful cosmological clock. The central black hole mass will be estimated based on a recently revised back hole mass – luminosity relationship. The time delay of the iron enrichment and the time required to form a supermassive black hole {logM>8 Msol, tau ~0.5Gyr} as evidenced by quasar activity will be used to date the beginning of the first intense star formation, marking the formation of the first massive galaxies that host luminous quasars, and to constrain the epoch when supermassive black holes start to grow by accretion.

WFPC2 10745


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 11027

Visible Earth Flats

This proposal monitors flatfield stability. This proposal obtains sequences of Earth streak flats to construct high quality flat fields for the WFPC2 filter set. These flat fields will allow mapping of the OTA illumination pattern and will be used in conjuction with previous internal and external flats to generate new pipeline superflats. These Earth flats will complement the Earth flat data obtained during cycles 4-14.


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


10463 – REacq(1,2,1) failed to RGA Control

Upon acquisition of signal at 283/14:02:15, REacq(1,2,1) scheduled at 283/13:53:22 – 14:01:26 was observed to have failed to RGA Hold due to search radius limit exceeded on FGS-1. One 486 ESB “a05” (FGS Coarse Track failed – Search Radius Limit Exceeded) was received at 283/14:02:15. Pre-acquisition OBADs had (RSS) attitude error corrections values of 34.82 and 29.85 arcseconds. ESB 1805 (FHST moving target detected) was received at 283/13:36:14 pre-acquisition. Post-acquisition OBAD/MAP not scheduled.

10466 – Vehicle not in Fine Lock upon AOS

Upon acquisition of signal at 284/02:01:34 vehicle was not in fine lock. Unknown if this is failure of REACQ(2,1,2) at 01:21:33 or a loss of lock. Initial GSACQ(2,1,1) at 284/00:03:44 was nominal.



1533-3 – Open ACS HRC CEB ACPC@+35V

                        SCHEDULED      SUCCESSFUL 
FGS GSacq               07                   07 
FGS REacq               06                   05 
OBAD with Maneuver  26                   26 

SpaceRef staff editor.