Science Capabilities of the Cosmic Origins Spectrograph

1. Science Capabilities of the Cosmic Origins Spectrograph James C. Green University of Colorado

2. COS Performance Philosophy • Maximum sensitivity with adequate spectral resolution • Sensitivity depends on both: • Large effective area (large signal) • Low scatter gratings, low background detectors (low noise)

3. The data demonstrate the capabilities • Rather than show curves of Aeff, /, dark current, fixed pattern noise, etc. I will show you the data

4. Representative Sample • IGM Science • ISM Science • Exo-planet science • Brown Dwarf Science • T-Tauri Stars • Time resolved spectroscopy • NUV Imaging

5. IGM Science

6. The Power of COS for IGM Studies • PKS0405 • z=0.573, F = 2e-14 ergs/cm2/s/Å • 9.7 ksec (G130M) vs. 27 ksec (STIS) gives substantial S/N improvement • 10-30x more sensitive than STIS; up to 100x more efficient for faint targets • Survey capabilities • Spatial mapping • Metals, diffuse IGM • To • 47 IGM sightlines observed, 200 hrs (GO, GTO, ERO) • Total Ly pathlength z = 12.92 • COS has already 5.5x the pathlength and 8.6x the number of absorbers of previous GHRS+STIS

9. Weak Lines We can see the weak features. 8±4 mÅ 9±1 mÅ 115±3 mÅ S/Nres=52 COS/G130M S/Nres≈ 8 STIS/E140M IGM Lyman systems on the QSO PKS0405 sightline (Charles Danforth)

11. He II Analysis HE2347-4342, z = 2.905 Shull, France, Danforth et al. - submitted

13. A broad range of other topics are being investigated OVI, HI-free Three probes of a single galaxy halo BLAs as WHIM tracers

14. ISM Science

15. ISM Science Cyg OB2 8a sightline: superposition of several diffuse clouds. HD 204827 sightline: (probably single) translucent cloud.

16. C II Comparison

17. CO Comparison

18. ISM Science Cyg OB2 8a sightline: superposition of several diffuse clouds. HD 204827 sightline: (probably single) translucent cloud.

19. Exo-Solar Planet Science Exo Solar Planet Science

20. Extra-solar Planets • Transit observations of HD209458b • Transit seen in Ly, OI, CII in STIS observations: are transit depths indicative of planetary “blow-off”? • Transit seen in CII (-40 to +40 km/s), Si III (-30 to +40 km/s) • Roughly 11% in CII and 8% in Si III • Larger than 1.5% disk eclipse suggests extended absorbing atmosphere in lines • Velocities consistent with escape speed (42 km/s)

22. France et al. (2010) : Cross-correlation analysisfinds a 3.8 emission feature at 1582Å in the G160M spectrum. • Consistent with H2 B-X (2-9) P(4), fluorescently excited by OI 1302 emission from HD209458. • Consistent with suppressed e- impact and Ly-pumped H2 relative to Jovian planets due to low B-fields and thick HI atmosphere.

24. Brown Dwarf Science

25. UV Emission in Brown Dwarfs • H2 line profile gives location of emission at dust sublimation radius/inner edge of the accretion disk • Emission from CIV and NV but no SiIV or MgII • indicating refractory material has sublimated onto grains • emission from hot gas in accretion flow rather than magnetosphere • Second, narrow component: from companion? • France et al. 2010, ApJ, 715, 596 24 Mjup (M8) 6 Mjup

26. 2M1207

27. T Tauri Star Science

31. H2B-X (0-5) R(1)+R(0) (0-5) P(2) (0-5) R(2) (2-5) R(11) (0-5) P(1) SiIV n+b FUV continuum

32. Time Resolved Spectroscopy • A flare occurred during the observation of a late type (naked) T Tauri Star

34. Si IV

35. C II

36. N V

37. Si III

38. NUV Imaging

40. Conclusions • COS is capable of observing fainter objects than previously possible, delivering high S/N spectra of targets addressing a wide variety of areas in astronomy.