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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-6162
DTSTART:20201015T203000Z
DTEND:20201015T220000Z
DTSTAMP:20260415T005518Z
LAST-MODIFIED:20201013T171215Z
LOCATION:Zoom meeting(see Abstract ) Coffee and tea 3:30pm\, Talk 3:45
  PM
SUMMARY:` JWST status as of 2020\, and some of its first Science Progr
 ams: Time Domain Science\, Cluster Lensing \\& Caustic Transits ''\, A
 stronomy Colloquium\, Rogier Windhorst\, Regents' and Foundation Profe
 ssor\, JWST Interdisciplinary Scientist\, Arizona State
DESCRIPTION:In this talk\, I will give the 2020 summary of the 6.5 met
 er James Webb Space Telescope (JWST)\, the near--mid-IR sequel to both
  Hubble and Spitzer. All hardware has been built\, and is in the final
  stages of testing for its launch scheduled in October 2021. Next\, I 
 will review some of the early science that JWST plans do starting in 2
 022\, inspired by Hubble Wide Field Camera 3.<br>
\n<br>
\nJWST can do
  unique time domain science to 29 mag in the North Ecliptic Pole (NEP)
 Time-Domain Field (TDF) located in JWST's (and HST's) northern Continu
 ous Viewing Zone: a unique clean region devoid of bright foreground st
 ars with low Galactic extinction. JWST can observe most targets for 2x
 2 months per year\, including the well known HST and Spitzer deep fiel
 ds\, but can observe the NEP TDF at all times\, so that NIRISS paralle
 l grism spectra will always cover NIRCam 0.8-5 micron images 180 days 
 later. Since 2016\, the JWST TDF has been observed from space and the 
 ground\, from hard X-rays to long wavelength radio. The NEP TDF will s
 earch for and monitor high redshift transients: SNe at z>5\, weak Acti
 ve Galactic Nuclei\, Galactic brown dwarf atmospheres\, and provide pr
 oper motions of nearby brown dwarfs\, low-mass stars\, and ultracool w
 hite dwarfs to 29 mag\, and perhaps some Inner Oort Cloud Objects.<br>
 
\n<br>
\nThe search for first galaxies at redshifts z=9-11 (cosmic ag
 e ~0.5 billion yrs) in Hubble's Deep Fields has shown what combination
  of area\, depth\, and wavelength coverage is needed for JWST to detec
 t a sufficient number of First Light objects.  Since the Schechter lum
 inosity function likely drops rapidly in amplitude atz>7-8\, gravitati
 onal lensing by the best rich foreground galaxy clusters is essential 
 to maximize the number of First Light objects (z ~ 7-17) detected with
  JWST. To address the observability of objects in the First Light epoc
 h\, I willuse panchromatic Extragalactic Background Light to to constr
 ain the integrated near-IR surface brightness (SB) that may come from 
 Population III stars and their stellar-mass black hole (BHs) accretion
  disks.<br>
\n<br>
\nThe physical properties of zero-metallicity Pop I
 II stars from MESA stellar evolution models through helium depletion\,
  and BH accretion disk models at z>7 provide an estimate of the number
  of caustic transits behind lensing clusters that JWST may detect for 
 both these objects. Typical caustic magnifications can be 10^4-10^5x\,
  with rise times of hours and decline times of z~<0.5 year for cluster
  transverse velocities of v_T<~1000 km/s. Microlensing by intracluster
 -medium objects can modify transit magnifications\, but lengthen visib
 ility times. To observe Pop III caustic transits directly with JWST ma
 y require monitoring 3-30 lensing clusters to AB<29 mag for <5-10 year
 s.<br>
\n<br>
\nZoom Meeting information:<br>
\n<br>
\nhttps://us02web
 .zoom.us/j/81750055728?pwd=T3Y5c1lYZjNnb1ZOWUI1ZXhKMlZBQT09<br>
\n<br>
 
\nMeeting ID: 817 5005 5728<br>
\nPasscode: 000018
URL:https://www.physics.wisc.edu/events/?id=6162
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