Direct Imaging of Galactic Winds in Extreme Starburst Galaxies

0 Assigned ID: 899 ----- Attempting Submission 1 (Fri Apr 10 21:58:11 GMT 2015) ----- HST Phase I Proposal 899 (tremonti_hst23_v2.apt) successfully submitted. Receipt: # 899-1 FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser I had previously excecuted a POS-TARG in visit 1 to place the bright star onto the chip at certain orients. However, as these orients did not have guide stars, I eliminated the POS-TARG move. 2136785336 ----- Attempting Submission 1 (Wed Jul 22 19:25:35 GMT 2015) ----- ----- Attempting Submission 2 (Thu Jul 23 18:07:13 GMT 2015) ----- HST Phase II Proposal 14239 (Tremonti_HST_Phase2_cy23_14239_v2.apt) successfully submitted. Receipt: # 14239-2 ----- Attempting Submission 3 (Thu Jul 23 18:33:59 GMT 2015) ----- For all exposures there are warnings about the background counts being too low. However, the APT calculations assume a low zodiacal background. I have used the ETC with the actual background appropriate for each target in calculating the amount of post flash to add. Direct Imaging of Galactic Winds in Extreme Starburst Galaxies Without strong feedback and efficient quenching of star formation, it is impossible for numerical simulations to reproduce a realistic galaxy population. To understand how this feedback process works, a crucial parameter that observations can constrain is the mass ejected in galactic winds. Unfortunately, there are order-of-magnitude uncertainties associated with estimates of mass outflow rates, particularly for winds that are detected via blueshifted absorption lines towards distant star-forming galaxies. This is primarily because the geometry and spatial extent of the wind cannot be measured directly and the inferred mass outflow rate scales as r_wind^2. One promising technique is to search for extended emission associated with resonantly scattered line photons from the wind. In practice, this is quite difficult to do with ground-based observations, which lack the required sensitivity and spatial resolution. Here we propose to use the unique medium-band imaging capabilities of HST to directly image the winds associated with two massive galaxies at z=0.6 that have recently experienced a feedback-limited starburst and are known to exhibit high-velocity, galactic scale outflows. We will measure (or place robust limits on) the geometry and spatial extent of these galactic winds as traced by resonantly scattered Mg II photons. This provides a unique opportunity to measure the mass outflow rate and energetics of these powerful winds and to quantify their role in the quenching of star formation. We are proposing to measure the morphology and spatial extent of the galactic winds in two extremely compact starburst galaxies at z = 0.46 and z = 0.66 using WFC3 imaging. We will trace low ionization gas in the wind using resonance emission from Mg II 2800 A which will be at wavelengths of ~4100 and ~4650 A in the observed frame. We are using the F410M and F467M filters to isolate the wind emission. Both filters are well centered on the line and span the range of velocities we expect to observe. Assuming that the wind has a shell-like geometry and spatial extent of 6 kpc, we expect the peak surface brightness to be 5e-18 erg/s/cm^2/A/arcsec^2. In our medium band filters, we will reach S/N~8-10 in a 3 x 3 pixel area centered on the brightest part of the shell in 4 orbits. A major concern in our medium-band Mg II imaging is contamination by faint stellar light. We are helped by the fact that our galaxies have very compact light distributions. However, since they are the products of recent major mergers, faint extended tidal features are also present. In order to subtract the stellar light from the filter containing Mg II we are obtaining single-orbit off-band images in F390W. The F390W images will be combined with existing F475W and F814W images to model and remove the continuum in the on-band filter. In the inner regions of the galaxy the major source of stellar light will be the wings of the PSF. Hence it will be important for the on- and off-band images to be taken at the same epoch and telescope role angle. For this reason we have opted to place all 5 orbits associated with an individual target in a single visit. We are using a box-dither to obtain optimal PSF sampling of our target. Due to the low background in our F390W, F410M, and F467M images CTE is a concern. The spatial extent of the outflow is expected to be small (< 200 pixels). We have therefore opted to place the targets close to the readout axis at the UVIS2-C1K1C-CTE position. In addition, we have added post flashes to our exposures to achieve a background of ~12 electrons. While there are some warnings generated about our background being too low, these automated calculations use a low zodiacal background. We have set the post-flash values based on ETC calculations using the actual zodiacal background of the target. We have constrained the orientations to prevent scatted light from bright stars near the edge of the chip. (We only care about +/-400 pixels form the target, so figure 8 ghosts are not a concern.) For Vist 1 (J1107), the orient constraints drastically reduced the visibility. For that reason we shotened the orbit duration slightly to free up some new visibility windows in November. ISM IN EXTERNAL GALAXIES 12 false false false false SUPPORTED GALAXY STARBURST YES J2000 J2000 GALAXY STARBURST YES J2000 J2000 WFC3/UVIS Imaging No No F410M WFC3/UVIS Imaging No No F390W WFC3/UVIS Imaging No No F467M WFC3/UVIS Imaging No No F390W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1

false

1437675908885 /private/var/folders/1s/jbw8fdfn7g32s505cypm2_4h0000gn/T/OPVisit1057147372037380943.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14239 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "23-Jul-2015 13:25:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 3464944 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14239 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14239 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2864 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2976 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2976 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2976 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "01" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2976 :al-overhead-at-end 120 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) true 5 0 APT warns that the background is too low, however it assumes a "low" value of the zodiacal light. Using the ETC with the zodiacal light apporiate for the targets RA/DEC, this flash level is adquate APT warns that the background is too low, however it assumes a "low" value of the zodiacal light. Using the ETC with the zodiacal light apporiate for the targets RA/DEC, this flash level is adquate (11.7 e-/pixel) APT warns that the background is too low, however it assumes a "low" value of the zodiacal light. Using the ETC with the zodiacal light apporiate for the targets RA/DEC, this flash level is adquate (11.7 e-/pixel) 1437589267212 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14239 :visit-id "02" :proposal-version -1 :trans-version "20150609" :date "22-Jul-2015 13:21:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 3464944 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14239 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14239 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2876 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2988 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2988 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "02" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2988 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14239 :visit-id "02" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2988 :al-overhead-at-end 120 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) true 5 0 APT warns that the background is too low, however it assumes a "low" value of the zodiacal light. Using the ETC with the zodiacal light apporiate for the targets RA/DEC, this flash level is adquate APT warns that the background is too low, however it assumes a "low" value of the zodiacal light. Using the ETC with the zodiacal light apporiate for the targets RA/DEC, this flash level is adquate APT warns that the background is too low, however it assumes a "low" value of the zodiacal light. Using the ETC with the zodiacal light apporiate for the targets RA/DEC, this flash level is adquate