HETE-2 (High Energy Transient Explorer)

a small satellite for studying the cosmic gamma-ray bursts

and beyond ….

Atsumasa Yoshida (RIKEN)

HETE history

1983— recommended in Santa Cruz meeting Feb 1991— official start of HETE US - Japan - France collaboration multiwavelength study of GRB in UV, X-ray and gamma-ray real-time localization and rapid notification

Nov 1996— HETE-1 launch: lost in failure of 3rd stage separation

Feb 1997— Discovery of GRB afterglow HETE concept proven, (but by different mission)

Jul 1997— HETE-2 started UV camera replaced by Soft X-ray Camera in HETE-2

HETE-1 mounted on the Pegasus rocket. The small red object immediately to the left of the solar panel is a set of pyrotechnic bolt cutters, which releases the satellite from the third stage. The second and third stages of the rocket can be seen.

HETE-1

HETE-1

HETE-1 inside the DPAF (Dual Payload Attachment Fitting) can. This structure protects HETE-1 while SAC-B is deployed.

3rd stage + HETE + SAC-B attached.The third stage is the short, black unit behind the DPAF can (along with the instrumentation ring and RCS systems ring), attached to the white second stage. This assembly is still circling the earth as one unit, after failure of the 3rd stage pyrotechnics to release both satellites.

HETE-1 Launch in November 1996 ... and Lost

HETE-2 Instruments

Optical Camera

Soft X-ray Camera

Wide-field X-ray Monitor

French Gamma-rayTelescope

The HETE Mission

Prime objective: multiwavelength study of gamma ray bursts (GRBs) with soft/medium X-ray, and gamma ray instruments

Unique feature: capability to localize bursts with several arcsecond accuracy, in near real-time aboard the spacecraft

GRB positions transmitted to the global network of primary and secondary ground stations, enabling sensitive follow-up studies

Primary Science Goals: GRBs

provide accurate postions (±10 arcsec to ±10 arcmin) for ~30 bursts in real time each year.

factor of ~4 more sensitive than the BATSE SDs for low energy spectral features and will provide ~25 GRBs per year on which high-quality spectral studies can be performed.

The 2-25 keV and 3-400 keV sensitivities of the X-ray and gamma ray instruments: effective for studying cyclotron lines and spectra of GRBs at low energies.

~7.5 times more sensitive than BATSE to bursts from Soft Gamma Ray repeaters: event rate ~ 55 times higher than BATSE.

Secondary Science Goals

detect as many as 500-1000 X-ray bursts per year. monitor the evolution of X-ray bursts and X-ray

transients in the FOV of the X-ray detector. discover and study X-ray pulsars for ~2 month

intervals. discover and study black hole transients .

Spacecraft Specification

Mass: 126 kg. Envelope: Fits within cylinder 89cm x 66 cm dia. Desired orbit: 600 km circular, 0 degree inclination Operating life: 6 months, nothing to preclude 2+ years Attitude: Sun pointing. Momentum bias. Attitude controlled to

+/- 2 degrees Data processing: Multi-processor, 80 VAX MIPS Data Buffering: 96 MBytes of EDAC mass memory Downlink: 250 kbits/sec data rate with overall bit error rate <2e-8 f

rom data storage to ground archive. Uplink: 31.25 kbits/sec data rate, overall bit error rate < 1e-8 Radio Frequencies: S-band uplink (2.092 GHz) and

downlink (2.272 GHz) for primary groundstation(s),

VHF downlink only (137.9622 MHz) for secondary stations.

FREnch GAmma-ray TElescope(FREGATE)

Built by CESR (France) Instrument type NaI(TI);cleaved Energy Range 6 keV to > 1 MeV Timing Resolution 4 ms Spectral Resolution ~40% @ 6 keV

~7% @ 662 keV Effective Area 120 cm2

Sensitivity (10 ) 3x10–8 erg cm–2 s–1 over 8 keV—1 MeV

Field of View ~2 sr

Wide-field X-ray Monitor (WXM)

Built by RIKEN and Los Alamos National Laboratory Instrument type Coded Mask with

Position Sensitive Proportional Counter Energy Range 2 to 25 keV Timing Resolution 1 ms Spectral Resolution ~15% @ 6 keV Detector Quantum Efficiency 90% @ 5 keV Effective Area ~200 cm2 for each of two units Sensitivity (10 ) ~8x10–9 erg cm–2 s–1

over the 2-10 keV range Field of View ~2 sr (total for 4 units) Angular resolution (1 ) ±6 arcmin

WXM

Two-layered multi-wire proportional counter

Be window 10mcarbon wire Gas mixture: Xe (97%)

+CO2 (3%) Gas pressure 1.4atm

GRB localization with1-D position sensitive detectors

}coded mask

1-dim. PC

mask pattern (top view)

shift pattern A

shift pattern B

shift pattern C

WXM (side view)

WXM localizes GRB's by measuring the mask pattern displacement for two orthogonal directions.

Soft X-ray Camera (SXC)

Built by MIT CSR Instrument type 4 CCD20 Detectors, 2 optical CCD22 Camera dimensions 10cmx10cmx17.5cm Energy Range 500 eV to 14 keV Timing Resolution ~1 s Spectral Resolution 46 eV @ 525 eV,

129 eV @ 5.9 keV Detector Quantum Efficiency 93% @ 5 keV,

>20% (0.5-14 keV) Effective Area 6.1x6.1 cm2 (each of 2 units) Burst Sensitivity (4 ) 0.47 cts cm–2 s–1

Steady source Sensitivity (4 ) ~700 mCrab x t –1/2

Field of View 0.91 sr Focal Plane scale 33" per CCD pixel Loaclization Precision Faint Burst, 5 - 15",

Bright burst, 22 , 3" (1 Crab; 10s)

HETE2 Operation Network

Ground-based Observatory 　 (Optical, Radio, γ -ray )

HETE-2

RIKEN

Primary Ground Station

SecondaryGroundStationInternet

Data & Command

GRB positioninformation

Gamma Ray Burst

MIT

VHF

S band

Secondary Ground Station Network

* Primary Ground Station

23 4

56

7

8

9

10

11 1

1 Kwajalein * 167.7 E 8.7 N 2 Christmas Island 157.1 W 1.9 N 3 Hiva Oa (French Polynesia) 139.0 W 9.8 S 4 Galapagos Island (Ecuador) 91.1 W 0.7 S 5 Cayenne (French Guiana) * 51.9 W 4.9 N 6 Natal (Brazil) 35.1 W 5.5 S 7 Accra (Ghana) 0.2 W 5.6 N 8 Malindi (Kenya) 40.2 E 3.0 S 9 Male (Maldives) 73.7 E 3.6 N 10 Singapore * 103.8 E 1.3 N 11 Koror (Palau) 134.5 E 7.3 N

Vibration Test

Lincoln Lab - MITAugust 1999

Thermal Vacuum Test

Lincoln Lab - MITAugust-September 1999

Primary Ground Station in Singapore

National　University　of　Singapore

Launch in January 2000

The HETE-2 is scheduled to be launched in January 2000 from Kwajalein, Republic of the Marshall Islands.

ROTSERobotic Optical Transient Search Experiment

OPTICSCanon 200 mm focal length, f/1.8, telephoto lenses in FD mounts

IMAGERApogee Instruments AP-10 CCD cameras with Thomson 2048 x 2048 14 micron imagers.Estimated readout noise: 25 e- at 1.0 Megapixels/sec.

University of Michigan. Los Alamos National LaboratoryLawrence Livermore National Laboratory

Optical Flash! Up to 9 mag

UTC exposure m_v

9:47:18.3 5 secs. 11.829:47:43.5 5 secs. 8.959:47:08.8 5 secs. 10.089:51:37.5 75 secs. 13.229:54:22.8 75 secs. 14.009:57:08.1 75 secs. 14.53

ROTSE(Optical)

BATSE(gamma-ray)

GRB 990123: Optical Transient

ROTSE-II

ROTSE-II is a set of twin 0.45 meter aperture, f/1.9 telescopes to be operated in stereo mode.

Apogee Instruments AP-10 CCD cameras with Thomson 2048 x 2048 14 micron imagers.Estimated readout noise: 25 e- at 1.0 Megapixels/second.

LOTIS Livermore Optical Transient Imaging System

2 x 2 array of Canon EF 200 mm f/1.8L telephoto lenses w/ Loral 442A 2k x 2k CCDs as the imaging sensors.

Each focal plane area of 3.1 cm x 3.1 cm --- a field-of-view for each camera of 8.8° x 8.8°.

The total field-of-view for the telescope array (allowing for overlap) is therefore 17.4° x 17.4°.

The CCD pixel size of 15 μm x 15 μm results in a pixel resolution of 15 arcsec.

Super-LOTIS

Telescope: Boller & Chivens 0.6 meter f/3.5 reflector w/ computer controllable motor drive.

Imager: a Loral 442A 2048 x 2048 CCD (15 x 15 micron pixels) with LLNL built readout electronics. The CCD is cooled with thermoelectric cooler (to -30 degrees C).

Field-of-View: 0.84 x 0.84 degree field-of-view (1.5 arcsec/pixel).

Resolution - < 1.5 arcsec Sensitivity - V ~ 19 (10 s), V ~ 21 (6

0 s) at -30 deg C Slew Speed - 5 deg/s

RIBOTSＲＩｋｅｎ - Ｂｉｓｅｉ Ｏｐｔｉｃａｌ Ｔｒａｎｓｉｅｎｔ Ｓｅｅｋｅｒ

望遠鏡 LX200-30 シュミットカセグレン 口 径 300mm 焦点距離 1000mm (0.33 倍 RD 使用 ) 視 野 47.2 ‘X 31.4‘ 導入速度 秒速 6° 冷却ＣＣＤ ST8E (KAF1600E) 画素数 1530x1020 (160 万画素 ) ２ × ２ ： ７６５ × ５１０ 角度分解能

３．７“ ３ × ３ ： ５１０ × ３４０ 角度分解能

５．６“ 波長帯 350 ～ 925nm (QE > 20%) フィルターなし

RIBOTS　Specification

Swift Catching Gamma Ray Bursts on the Fly

Multiwavelength gamma ray burst observatory

Science Determine origin of GRBs Use GRBs to probe the early

Universe

Three instruments Gamma-ray camera X-ray Telescope UV and Optical Telescope

Rapidly re-pointing “swift” spacecraft

20-70 s response

Swift Mission Features

Rapid response satellite

20 - 70 sec to slew within FOV of BAT

autonomous operations factor 100 improved response time continue monitoring of fading afterglow

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 opticalafterglow 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

Swift Instrumentation

Real time gamma ray burst positions

half coded FOV 2 steradians

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 arcmin giving positions of 1-4 arcmin

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

Burst Alert Telescope (BAT)

BAT CdZnTe detector module

Swift mission summary

PI: N. Gehrels (GSFC) Narrow Field Instruments - Penn State lead

• X-ray Telescope & Focal Plane (XRT) - Penn State/Leicester/Brera • UV/Optical Telescope (UVOT) - MSSL/Penn State/UCSB

Burst Alert Telescope (BAT) - GSFC lead• Camera and mask - GSFC• Onboard processing - Los Alamos

LEO orbit, 600 km circular 19 degree inclination Launch date 2003 Three-year mission operation life Orbit stable for 5+ years without propulsion

Space Missions Capable of Localizing Gamma-Ray Bursts

Mission loc/yr accuracy delay operating period

BeppoSAX 10 1—10 arcmin hours present — 2001?

CGRO BATSE 300 >4° 5 sec present — 2002?100 >1.6° 15 min

Interplanetary 70 5’x 10° ~1 day present —2001?network (IPN ） 1’x 20’

RXTE ASM 4 10 arcmin hours present — 2002?

HETE-2 WXM 30 10 arcmin ~10 sec 2000 —2001 SXC 16 10 arcsec

INTEGRAL IBIS 20 arcminutes ~10 sec 2001—2003

Swift BAT 300 1—4 arcmin 12 seconds 2003(2004)—2010 XRT ~arcsec 50—70 sec UVOT 0.3 arcsec 200 sec

GLAST (>100 MeV) 50 10 arcmin 2005— (GBM) (200) (arcmin-arcsec) (10—300 sec)