13839( 5) - 07-Nov-2014 00:45:29 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13839 Version: 5 Check-in Time: 07-Nov-2014 00:45:29 STScI Edit Number: 2 Title The Lyman Alpha Extended Halo of a Quasar at z>6 ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Emanuele Paolo Farina Max-Planck-Institut fur Astronomie, Y Heidelberg CoI: Dr. Fabian Walter Max-Planck-Institut fur Astronomie, N Heidelberg CoI: Dr. Benjamin Weiner University of Arizona Y CoI: Dr. Roberto Decarli Max-Planck-Institut fur Astronomie, N Heidelberg CoI: Dr. Bram Venemans Max-Planck-Institut fur Astronomie, N Heidelberg CoI: Eduardo Banados Max-Planck-Institut fur Astronomie, N Heidelberg ------------------------------------------------------------------------------------ Abstract The formation of quasars at z>6, when the Universe is less than 1Gyr old, require enormous reservoirs of gas to feed the black hole growth on such a short time scale. The only effective way to map the presence of this key ingredient of the galaxy formation at high-z is through the detection of the extended and diffuse Ly-Alpha emission that is powered by the star-formation and by the UV emission of the quasar. We here propose to observe the extended Ly-Alpha emission associated to the most powerful radio-loud high-redshift quasar known so far (J1429+5447, z=6.18). Radio-loud quasars are expected to be extremely biased tracers of the most massive dark matter halos and to be the precursor of the massive elliptical galaxies observed at z=0. The grism spectroscopy mode of the WFC3/IR camera provides the unique opportunity to directly investigate the properties of the Ly-Alpha ionized gas associated to the first quasars, putting strong constraints on the processes involved in the formation of the first galaxies at the end of the Cosmic reionization. ------------------------------------------------------------------------------------ Observations Description ------------------------ Observing Description for HST Cycle 22 Proposal 13839 The Lyman Alpha Extended Halo of a Quasar at z>6 PI: Emanuele Paolo Farina - emanuele.paolo.farina@gmail.com ---------------------------------- Goal of the observations ---------------------------------- This proposal aims to map the Ly-alpha emission in the immediate environment of the radio-loud quasar 13839( 5) - 07-Nov-2014 00:45:29 - [ 2] J1429+5447 at z=6.18 using slitless spectroscopy with the WFC3-IR G102 grism. The central goal of the programme is the detection of the extended Ly-alpha halo that surround the quasar's host galaxy. This diffuse emission is redshifted to 8730Ang. and it is expected to occur on scale of ~7 arcsec (in diameter) with a line surface flux of ~9e-17 erg/s/cm2/arcsec2. Coincidentally the CIV emission line fall within the spectral range covered by the G102 grism (at 11100Ang.), and will allow to set constraints on the metal enrichment and on the physical status of the nebula. The discovery spectra of the quasar (blue solid line), the SDSS quasar template shifted at z=6.18 (gray dashed line), and the throughtput curve of the G102 grism (red shaded area) are shown here: https://www.dropbox.com/s/jler96akskmeums/spectra.eps This observations have the additional promise to resolve the interstellar medium of the quasar's host galaxy on scales <1 arcsec and to reveal -- through their Ly-alpha emission -- faint companion galaxies present in the vicinity of quasar. A total of 6 orbits are scheduled for this project, that will be splitted in two different visit with two different orientation angles (see below). ---------------------------------- Observing strategy ---------------------------------- ** Orbit / visit strategy: We consider to obtain the observations at two differenent roll angles (2 visits of 3 orbits each) which lead to different inter-object contamination and allow to accurately separate the single contributions. In each visit, we use 6 dither positions. At each position, we take a short direct F105W reference image and two long grism G102 science exposures. The reference images are mandatory to accurately locate the position and the size of the sources in the field of view, making the data easier to reduce. In the first visit, the direct exposures are ~150 sec long (SPARS25 x NSAMP=7) and the grism exposures are ~1300 sec (SPARS100 x NSAMP=14) or ~1400 sec long (SPARS100 x NSAMP=15) when the shorter time used for pointing the telescope in the 2nd and 3dt orbits allows to increase the integration time. During the second visit the visibility is limited by the considered orientation angle, thus the direct exposures are ~150 sec long (SPARS25 x NSAMP=7) or 13839( 5) - 07-Nov-2014 00:45:29 - [ 3] ~130 sec long (SPARS25 x NSAMP=6) and the grism exposures are ~1300 sec (SPARS100 x NSAMP=14) or ~1200 sec long (SPARS100 x NSAMP=13). The order of exposures within an orbit is: grism, direct, direct, grism. ** Dithering: We use POS-TARG offsets to make the dithers. Each direct image -grism pair has the same set of POS-TARG offsets. The 6 point-dither pattern we consider in each visit is similar to the pre-defined patterns WFC3-IR WFC3-IR-DITHER-LINE-3PT and WFC3-IR-DITHER-LIN combined togheter, i.e. we make use of WFC3-IR WFC3-IR-DITHER-LINE-3PT two times shifted of +3.5 -3.5 between each others: x-pixel y-pixel x-POS-TARG y-POS-TARG 0.00 0.00 0.000 0.000 3.33 3.33 0.450 0.403 6.67 6.67 0.900 0.806 10.17 3.17 1.373 0.384 6.83 -0.17 0.922 -0.021 3.50 -3.50 0.473 -0.424 where x-POS-TARG y-POS-TARG are given in arcsec. ** Position Angle: We set two different position angle, one for each visit, to obtain different inter-object contamination and to separate the single contributions. The angles are selected to avoid the superposition from of the spectrum of J1429+5447 with those of close by stars and galaxies (for details see comments on the single visits and the figure here: https://www.dropbox.com/s/9bcwgvtn9md9vba/J1429p5447_cont.jpeg ). ------------------------------------------------------------------------------------ 13839( 5) - 07-Nov-2014 00:45:29 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J1429+5447 GALAXY, EMISSION LINE RA=14H29M52.1700S +/- 0.1", J2000 Z = z'(AB)=21.45, J(AB)=20.64, NEBULA, HIGH REDSHIFT DEC=+54D47'17.70" +/- 0.1" 6.183 LSF(HALO)=9e-17erg/s/cm2/arcsec2 GALAXY, QUASAR Reference Frame: ICRS Comments: Due to the redshift of the source (z=6.18), virtually no flux is expected at wavelenght shorter than ~8730Ang. Other Fluxes: LSF(HALO) is the estimated line surface flux of the Ly-alpha extended emission associated to the quasar. This is expected to fall within a single resolution element of the G102 disperser (FWHM<500km/s) and to have a radial extend of ~7 arcsec (i.e. 50 pixel). ------------------------------------------------------------------------------------------------------------------------------------ 13839( 5) - 07-Nov-2014 00:45:29 - [ 5] Visit: 01 Visit Requirements: ORIENT 171.0D TO 186.4 D On Hold Comments: Additional Comments: 3 orbits observation of J1429+5447. The orientation angle is setted in order to avoid possible 0th and 1st order contamination from the bright sources present in archivial F105W-band HST images of J1429+5447. These objects are marked with yellow (0th order) and green (1st order) circles in the finding chart: https://www.dropbox.com/s/9bcwgvtn9md9vba/J1429p5447_cont.jpeg We limit the magnitude of the possible contaminats to: m(F105W)<21 for the 0th order (5 objects at an angular separation from J1429+5447 of 40arcsec Additional Comments: 3 orbits observation of J1429+5447. The orientation angle is setted in order to avoid possible 0th and 1st order contamination from the bright sources present in archivial F105W-band HST images of J1429+5447. These objects are marked with yellow (0th order) and green (1st order) circles in the finding chart: https://www.dropbox.com/s/9bcwgvtn9md9vba/J1429p5447_cont.jpeg We limit the magnitude of the possible contaminats to: m(F105W)<21 for the 0th order (5 objects at an angular separation from J1429+5447 of 40arcsec