Results from the Refurbished Hubble 10/29/09

1. Results from the Refurbished Hubble 10/29/09

2. The Mission • STS-125: 5/11/09 – 5/24/09 • Fifth and final servicing mission to the 19-year old scope • 3 members of 7-person crew had been on earlier HST service missions • The 2/1/03 Columbia disaster cancelled the HST mission that had been schedule for late 2005

3. Mission Reinstatement (Wikipedia) Joining Mikulski as an advocate for servicing Hubble was NASA's Chief Scientist, physicist John Grunsfeld, who was present at the meeting when O'Keefe announced the cancellation of the mission.[18] A veteran astronaut of four shuttle missions, including two Hubble servicing missions, Grunsfeld had devoted years to Hubble, and was very disappointed when O'Keefe canceled the mission.[18] He briefly considered retiring from NASA, but realized if he stayed, he could continue to advance physics in other ways.[18] Instead, Grunsfeld dedicated himself to finding alternate ways to service the telescope, possibly by sending a robot into orbit to do the job.[18] When O'Keefe announced his resignation as Administrator in December 2004, five days after a National Academy of Sciences committee opposed O'Keefe's position regarding servicing Hubble,[19][20] the media and science community saw hope for the telescope's servicing mission to be reinstated.[21][22][Zimmerman 1]

4. More . . . O'Keefe's replacement, former NASA Administrator Michael D. Griffin took just two months after his appointment to announce that he disagreed with O'Keefe's decision, and would consider sending a shuttle to repair Hubble.[Zimmerman 2] As an engineer, Griffin had previously worked on Hubble's construction, and respected the discoveries the telescope brought to the science community.[Zimmerman 2] He agreed with the National Academy of Sciences that a robotic mission was not feasible, and said that in light of the Return to Flight changes made following the Columbia accident, a shuttle mission to repair Hubble should be reassessed.[Zimmerman 3] After the successes of the Return to Flight STS-114 and STS-121 missions, and the lessons learned and improvements made following those missions, managers and engineers worked to formulate a plan that would allow the shuttle to service Hubble, while still adhering to the post-Columbia safety requirements.[Zimmerman 1] On October 31, 2006, Griffin announced that the Hubble servicing mission was reinstated, scheduled for 2008, and announced the crew that would fly the mission, which included Grunsfeld.[NASA 9][23][24]

5. Mission Service Activities • Replaced WFPC2 with WFC3 • Replaced Science Instrument Command and Data handling Unit • Replaced three gyros and two battery modules • Removed COSTAR and replaced it with COS • Replaced electronics for ACS • Replaced electronics for STIS • Other replacements of supporting equipment

6. Instrumentation • COSTAR was the corrective device installed on the first service mission. Later instruments have been designed with their own corrective optics. • WFC3: Optical wavelengths with 2 CCD’s; (1024)2 near-IR array, 800 to 1700 nm. • ACS: Used for the HUDF before it broke in 2007. STS-125 restored the WFC, which registers 350 – 1100 nm.

7. The Wide Field Camera 3 (WFC3), a new camera aboard the Hubble Space Telescope, snapped this image of the planetary nebula, catalogued as NGC 6302, but more popularly called the Bug Nebula, or Butterfly Nebula. NGC 6302 lies within the Milky Way, roughly 3,800 light-years away in the constellation Scorpius. The glowing gas is the star’s outer layers, expelled over about 2,200 years. The “butterfly” stretches for more than 2 light-years, which is about half the distance from the Sun to the nearest star, Alpha Centauri. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

8. These two images of a huge pillar of star birth demonstrate how observations taken in visible (top) and in infrared light (bottom) by Hubble reveal dramatically different and complementary views of an object. Composed of gas and dust, the pillar resides in a tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away in the southern constellation Carina. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

9. Hubble snapped this panoramic view of a colorful assortment of 100,000 stars residing in the crowded core of a giant star cluster. The image reveals a small region inside the massive globular cluster Omega Centauri, which boasts nearly 10 million stars. Globular clusters, ancient swarms of stars united by gravity, are the homesteaders of our Milky Way. The stars in Omega Centauri are between 10 billion and 12 billion years old. The cluster lies about 16,000 light-years from Earth. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

10. A clash among members of a famous galaxy quintet reveals an assortment of stars across a wide color range, from young blue stars to aging red stars. This portrait of Stephan’s Quintet, also known as Hickson Compact Group 92, was taken by the new Wide Field Camera 3. Stephan’s Quintet, as the name implies, is a group of five galaxies. The name, however, is a bit of a misnomer. Studies have shown that group member NGC 7320, at upper left, is actually a foreground galaxy about seven times closer to Earth than the rest of the group. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

11. The wispy, glowing, magenta structures in this image are the remains of a star 10 to 15 times the mass of the Sun that we would have seen exploding as a supernova 3,000 years ago. The remnant’s fast-moving gas is plowing into the surrounding gas of the galaxy, creating a supersonic shock wave in the surrounding medium and making the material glow. The Hubble visible-light image reveals, deep within the remnant, a crescent-shaped cloud of pink emission from hydrogen gas and soft purple wisps that correspond to regions of glowing oxygen. A dense background of colorful stars is also visible. Probing this tattered gaseous relic, the newly installed Cosmic Origins Spectrograph (COS) aboard NASA’s Hubble Space Telescope detected pristine gas ejected by the doomed star that has not yet mixed with the gas in the interstellar medium. The supernova remnant, called N132D, resides in the Large Magellanic Cloud, a small companion galaxy of the Milky Way located 170,000 light-years away. The resulting spectrum, taken in ultraviolet light, shows glowing oxygen and carbon in the remnant. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

12. The Hubble Space Telescope’s newly repaired Advanced Camera for Surveys (ACS) has peered nearly 5 billion light years away to resolve intricate details in the galaxy cluster Abell 370. Abell 370 is one of the very first galaxy clusters where astronomers observed the phenomenon of gravitational lensing, where the warping of space by the cluster’s gravitational field distorts the light from galaxies lying far behind it. This is manifested as arcs and streaks in the picture, which are the stretched images of background galaxies. Gravitational lensing proves a vital tool for astronomers when measuring the dark matter distribution in massive clusters, since the mass distribution can be reconstructed from its gravitational effects. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

13. This image of barred spiral galaxy NGC 6217 is the first image of a celestial object taken with the newly repaired Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope. The camera was restored to operation during the STS-125 servicing mission in May to upgrade Hubble. The barred spiral galaxy NGC 6217 was photographed on June 13 and July 8, 2009, as part of the initial testing and calibration of Hubble’s ACS. The galaxy lies 6 million light-years away in the north circumpolar constellation Ursa Major. Image and caption: NASA, ESA, and the Hubble SM4 ERO Team

14. Background Info: Redshift vs Distance atlasoftheuniverse.com

15. Photometric Filters

16. Lyman Hydrogen Spectrum (WP)

17. Lyman-α Forest (WP)

18. Gunn-Peterson Trough (Becker, et. al.)

19. The Lyman Break • Lyman-break galaxy A galaxy with a very high redshift discovered from its red colour. Hydrogen is very effective at absorbing radiation with wavelengths shorter than 91.2 nm (the Lyman limit), and all galaxies contain large amounts of hydrogen; hence galaxies are virtually dark at wavelengths shorter than 91.2 nm. This dividing point in a galaxy's spectrum is termed the Lyman break. For a galaxy at a redshift of about 3, the Lyman break falls between the U and B photometric bands. The galaxy should therefore be seen in B but be virtually invisible in U, an effect called the U-band dropout. Encyclopedia.com

20. Lyman Break Galaxies Steidel, Hamilton, Pettini, Dickinson, Giavalisco and their collaborators

21. The Article • The filters: Y-band 1.1 um on the WFC3 and z’-band 0.85 um on the ACS (previous). • Look for z’-drops: (z’ – Y)AB > 1.3 and YAB < 28.5 • Use the WFC3 J-band image to reject low mass galactic stars • Calculate the star formation rate density for the candidate galaxies • Are the rates sufficient for reionization?

22. Figures • (1): z’-drops of the 12 candidates. See Table 1. • (2): (z’ – Y) values at increasing redshifts. Low redshift galaxies and dwarf stars can also appear above the 1.3 cutoff. • (3): LRG’s and dwarfs can be segregated with additional photometry • (4): Identifies the candidates

23. Figures (cont.) • (5): “Hence we strongly rule out the simple scenario of no evolution over the range z = 7 - 3 as the observed counts are 3 - 5 times too low • (6): Blueness of the z’-drops. “Such blue slopes could be explained through low metallicity, or a top-heavy IMF . . .” (Interplanetary magnetic field) • (7): z = 8(+) Y-drops

24. Estimates of Star Formation Rates • “We can use the observed Y-band magnitudes of objects in the z’-drop sample to estimate their star formation rate from rest-frame UV luminosity density.” (Relation provided on p 9).

25. Results • “. . . But even if we take fesc = 1 [] and a very low clumping factor, this estimate of the star formation density required (for reionization) is a factor of 1.5 - 2 higher than our measured star formation density at z = 7 from z’-drop galaxies in the UDF.”