Swift1

Swift Spacecraft and Instruments

Swift2

Spacecraft Design

1 of 6 Reaction wheels

Gyros

Star Trackers

Swift3

Swift OverviewCatching Gamma Ray Bursts on the Fly

Capabilities

~ 1000 GRBs studied over a three-year period

0.3–2.5 arc-second positions for each GRB

Multiwavelength observatory (gamma, X-ray,

UV, and Optical) to monitor afterglows

20–70 s reaction time

Five times more sensitive than BATSE

Spectroscopy from 0.2 to 150 keV

Six colors covering 170–650 nm

UV and optical spectroscopy with R ~ 300–600

for Mb < 17

Capability to directly measure redshift

Results publicly distributed within seconds

Swift4

Swift Mission Features

Multi-wavelength observatory

Burst Alert Telescope (BAT): 10-150 keV

detect ~ 300 gamma ray bursts per year onboard computation of positions arc-minute positional accuracy

Dedicated telescopes for X-rays, UV, and optical afterglow follow up:

0.3-10 keV X-ray Telescope (XRT) 170-650 nm UV/Optical Telescope (UVOT) 0.3-2.5 arc-second locations existing hardware from JET-X and XMM determine redshifts from X-ray absorption,

lines, and Lyman- cutoff Rapid response satellite

20 - 70 sec to slew within FOV of BAT

autonomous operations factor of > 100 improved response time continue monitoring of fading afterglow for days to weeks after the event

Swift5

Swift Instrumentation

Real time gamma ray burst positions

half coded 2 steradian FOV

5200 cm2 CdZnTe pixel array

10–150 keV band

based on INTEGRAL Imager design

5 times more sensitive than BATSE

~ 1 burst per day detected

(depends of logN-logS extrapolation)

angular resolution of 22 arc-minute giving positions of 1–4 arc-minute

onboard processing to provide prompt arc-minute position to satellite ACS and to the ground

I. Burst Alert Telescope (BAT)

BAT CdZnTe 8 x 16 element detector module

4 mm

Swift6

Swift Instrumentation

II. X-ray Telescope (XRT)

Flight spare JET-X module 15 arc-second half energy width

sharp core will yield arc-second locations 3.5 m focal length Total effective area

110 cm2 at 1.5 keV 65 cm2 at 6 keV

CCD array covers 0.2-10 keV band use spare XMM chip 24 x 24 arc-minute field of view Cooled to -80 degrees C

XRT Mirror Module

Swift7

Swift Instrumentation

Based on XMM OM to minimize cost and risk Covers 170 nm to 650 nm 30 cm Ritchey-Chretien telescope 24 mag in 1000 s with 17 arc-minute FOV Detector is image intensified CCD array Unique coverage 20-70 s after burst trigger Positions to 0.3 arc-seconds using onboard

image registration

UVOT will be simple reproduction of XMM OM

III. UV-Optical Telescope (UVOT)

Filter Wheel

XMM OM

Swift8

UVOT Performance

Wavelength

Pe

rce

nt

Tra

nsm

itta

nce

Measured UVOT Response

UV and optical grisms with of 0.5 nm and 1.0 nm, respectively, for Mb < 17

• IUE type resolution

UVOT Sensitivity

For V = 20 B star in 1000 s get:

UVW2 680 ctsUVM2 800 ctsUVW1 1000 cts

Sensitivity to Ly- cutoff:

UVM1 - UVM2 z ~ 1.5UVM1 - UVM1 z ~ 2U - UVW1z ~ 2.7B - U z ~ 3.5

Positions to 0.3 arc-seconds using onboard image registrations Filters give spectral/color information and allow redshift determination from Lyman edge detection

Swift9

Multiwavelength Cascade of Images

Gamma Ray (arc-minute)

X-ray (2.5 arc-second)

UVOT (0.3 arc-second)

HST, Keck, etc.

Swift10

Observing Strategy

Allow both onboard and external triggers (from, e.g., INTEGRAL) Slew to new burst as soon as possible

Follow all afterglows for as long as they are visible typically Swift will be monitoring a few afterglows

Time S/C Event Time POC Event

0 s GRB

10 s Slew Begins 12 s BAT location distributed

~ 50 s GRB acquired

55 s XRT image 62 s XRT location, BATlightcurves distributed

150 s UVOT findingchart

200 s Optical finding chartdistributed

1200 s XRT spectrum 1210 s XRT spectra distributed

7200 s UVOT filterscomplete

~ 104 s Ground stationpass

All burst data, Newobserving programuploaded