Status Report

NASA Hubble Space Telescope Daily Report #4479

By SpaceRef Editor
November 1, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report #4479

Notice: Due to the conversion of some ACS WFC or HRC observations into WFPC2, or NICMOS observations after the loss of ACS CCD science capability in January, there may be an occasional discrepancy between a proposal’s listed (and correct) instrument usage and the abstract that follows it.


– Continuing to collect World Class Science

PERIOD COVERED: UT October 30, 2007 (DOY 303)


NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments. 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.

NIC2 11197

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 that 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 Phillip’s relation over cosmic time. High signal-to-noise measurements of 16 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. In Cycle 15 we obtained NICMOS photometry of 8 ESSENCE supernovae and are awaiting template observations to place them on the IR Hubble diagram. Here we request another 8 supernovae be studied in the final season of the ESSENCE search. 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.

NIC2 11219

Active Galactic Nuclei in nearby galaxies: a new view of the origin of the radio-loud radio- quiet dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type galaxies {drawn from a complete radio selected sample} we have found evidence that the radio-loud/radio-quiet dichotomy is directly connected to the structure of the inner regions of their host galaxies in the following sense: [1] Radio-loud AGN are associated with galaxies with shallow cores in their light profiles [2] Radio-quiet AGN are only hosted by galaxies with steep cusps. Since the brightness profile is determined by the galaxy’s evolution, through its merger history, our results suggest that the same process sets the AGN flavour. This provides us with a novel tool to explore the co-evolution of galaxies and supermassive black holes, and it opens a new path to understand the origin of the radio-loud/radio-quiet AGN dichotomy. Currently our analysis is statistically incomplete as the brightness profile is not available for 82 of the 116 targets. Most galaxies were not observed with HST, while in some cases the study is obstructed by the presence of dust features. We here propose to perform an infrared NICMOS snapshot survey of these 82 galaxies. This will enable us to i} test the reality of the dichotomic behaviour in a substantially larger sample; ii} extend the comparison between radio-loud and radio-quiet AGN to a larger range of luminosities.

WFPC2 11167

A Unique High Resolution Window to Two Strongly Lensed Lyman Break Galaxies

On rare occasions, the otherwise very faint Lyman Break Galaxies {LBGs} are magnified by gravitational lensing to provide exceptional targets for detailed spectroscopic and imaging studies. We propose HST WFPC2 and NICMOS imaging of two strongly lensed Lyman Break Galaxies {LBGs} that were recently discovered by members of our team. These two LBGs — the “8 O’Clock Arc” and the “SDSS J1206+5142 Arc” — are currently the brightest known LBGs, roughly 3 times brighter than the former record-holder, MS1512-cB58 {a.k.a. “cB58”}. The z=2.73 “8 O’Clock Arc” extends ~10 arcsec in length and is magnified by a factor of 12. The z=2.00 “SDSS J1206+5142 Arc” also extends ~10 arcsec in length and is magnified by a factor of 30. Due to their brightness and magnification, these two strongly lensed LBGs offer an unprecedented opportunity for the very detailed investigation of two individual galaxies at high redshift. We are currently pursuing a vigorous ground-based campaign to obtain multi-wavelength {UV, optical, NIR, radio} observations of these two LBGs, but our campaign currently lacks a means of obtaining high-resolution optical/NIR imaging — a lack that currently only HST can address. Our prime objective for this proposal is to obtain high resolution HST images of these two systems with two-orbit WFPC2 images in the BVI bands and two-orbit NICMOS/NIC2 images in the J and H bands. These data will allow us to construct detailed lensing models, probe the mass and light profiles of the lenses and their environments, and constrain the star formation histories and rest-frame UV/optical spectral energy distributions of the LBGs.

WFPC2 11179

Dynamics of Clumpy Supersonic Flows in Stellar Jets and in the Laboratory

We propose to reobserve three stellar jets in order to quantify how rapidly clumps in these flows accelerate and decelerate, and to compare the results with ongoing numerical simulations and laboratory experiments. Each jet has been imaged twice before with HST, and precise proper motions have been measured for all emitting knots in the jets. Images from the first two epochs show clear differential motions between adjacent clumps, as well as shear, and possibly fragmentation. The proposed third epoch will enable us to measure the first ever accelerations in jets, quantify errors in existing proper motion measurements, and observe in real time how fluid instabilities develop in supersonic flows. The new images will make it possible to compare the behavior of astrophysical flows directly with numerical simulations and with laboratory experiments of bow shocks and clumpy flows in progress at the Omega laser facility.


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

HSTARS: (None)



                         SCHEDULED      SUCCESSFUL 
FGS GSacq               05                   05 
FGS REacq               08                   08 
OBAD with Maneuver      26                   26 


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