Selecting galaxies by their strong Lyman-alpha emission provides a powerful means of probing the reionization epoch and the faint/low-mass galaxies that dominate star formation at high redshift. Yet, our understanding of high-redshift Lyman-alpha emitters (LAEs) has lagged behind that of other well-studied populations (e.g., Lyman break galaxies) due to their continuum faintness and the shifting of age/mass-sensitive features into the near-IR where the high terrestrial background inhibits deep observations. All existing studies of LAEs at z>2 have used stacked optical and/or Spitzer infrared data to discern their median properties, but the actual distributions of ages, reddenings, and stellar masses for these populations are poorly characterized. To fill this glaring gap in the observations and advance our understanding of this important population, we propose WFC3/IR+F160W imaging of fields where we have conducted a survey of low redshift (z~1.9) Lyman-alpha emitters (LAEs), in order to measure their ages and stellar masses at an epoch where such observations directly probe the age-sensitive Balmer/4000 AA breaks. The targeted sample will include 45-50 spectroscopically confirmed LAEs at z=1.7-2.1 and roughly twice as many candidates, making it the largest sample of homogeneously selected LAEs with individual measurements of the ages, masses, and dust extinction. With these data we will (1) carefully take into account the age-dependence of the extinction curve to make robust comparisons between LAEs and continuum-selected galaxies at the same redshifts; (2) combine clustering and stellar mass measurements to infer the duty cycles of LAEs and determine if they are triggered in the presence of large-scale structures; and (3) quantify the importance of the LAE phase at different galaxy luminosity and mass scales, over a large dynamic range in these properties. An economical investment of just 12 orbits will allow us to accomplish these goals, and remains the only hope of efficiently studying such low luminosity high-redshift galaxies in the near-IR prior to the JWST-era.

Obtain WFC3/IR+F160W imaging in 12 separate pointings in the Bootes and Q1700 fields to study the stellar populations and stellar masses of strong Lyman-alpha emitters at redshift z~1.9 UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 false 0.0 0.0 false false false false false false SUPPORTED GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 35 3.9900 +33 25 15.55 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 34 45.9700 +33 26 23.47 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 34 37.8800 +33 24 18.00 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 35 2.7900 +33 22 46.45 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 34 38.5500 +33 27 52.27 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 29 24.6400 +32 46 0.78 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 29 13.9200 +32 43 53.19 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 14 29 9.9200 +32 49 42.17 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 17 00 19.5600 +64 05 16.02 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 17 00 12.6800 +64 07 58.32 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 17 00 21.2400 +64 13 7.99 J2000 GALAXY HIGH REDSHIFT GALAXY PROTOGALAXY J2000 17 00 36.3800 +64 15 32.77 J2000 WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 1 false POS-TARG DITHER 0.605 LINE false false 3 41.788 WFC3-IR-DITHER-LINE-3PT 2 false The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "01" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "02" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "03" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:10.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "04" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "05" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:14.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "06" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:15.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "07" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:16.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "08" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:18.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1949792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2885 :al-overhead-at-end 0 :internal-dur-at-end 692 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3275 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "09" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 08:12:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1636432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "09" :obset-id "09" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "09" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 616 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "10" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:19.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1636432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "10" :obset-id "10" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "10" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 616 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "11" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1636432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "11" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 616 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12224 :visit-id "12" :proposal-version -1 :trans-version "20100505" :date "07-Jul-2010 10:31:22.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1636432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12224 :visit-id "12" :obset-id "12" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12224 :visit-id "12" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 616 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) true 1 0