 than 100 X-ray sources from the All-Sky Monitor (ASM, built at CSR) provide a new global view of the nature of the variability of the X-ray sky. Observations of rapid periodic and aperiodic behavior from neutron stars and black holes with the large-area instrument continue probe the physics of these objects and the predictions of General Relativity (Professors H. Bradt, Chakrabarty, Lewin, Drs. Levine, E. Morgan, R. Remillard, Mr. Miller).

A major milestone for CSR was the successful launch of the High Energy Transient Explorer (HETE-2) in October 2000. Built and operated at MIT with US and international collaborators, HETE-2 is dedicated to detect and promptly locate the sources of gamma-ray bursts (GRBs). HETE-2 is now providing positions to the GRB community within seconds of a detected burst, and recently yielded the best measurement of the hard x-ray spectrum of a soft gamma repeater. (Drs. Doty, Crew, Ricker, Vanderspek, Villasenor, Mr. Monnelly).

In radio astronomy at least three new gravitational lenses have been discovered (Prof. Hewitt with Prof Schechter). Hewitt and colleagues at Haystack Observatory continue work on the development of a large low-frequency array, which will also serve as a prototype for the future Square Kilometer Array, with goals of mapping the first structures that formed in the universe.

MIT is a member of the Magellan consortium, which is building two 6.5-meter diameter optical telescopes in Chile. The first of these was dedicated in December 2000, and is now operating. MIT (with Harvard and Carnegie) completed a permanently mounted camera, guider, and wavefront sensing system. The camera has already been used to search for optical counterparts to neutron stars and X-ray bursters, and to study gravitational lenses. The second telescope will begin science operations in October 2002. (Professors Canizares, Chakrabarty, Elliot, Schechter, Sussman, Dr. Osip, Mr. Boughan).

Studies of plasma in the solar wind continue from three spacecraft: IMP 8 and Wind (both near Earth) and Voyager 2 (currently at 65 AU). This past year was near the maximum in solar activity, and many large interplanetary shocks were observed near 1 AU. Studies of shocks associated
than 100 X - ray sources from the All - Sky Monitor (ASM, built at CSR) leave a newfangled global view of the nature of the variability of the adam - ray sky. Observations of rapid periodic and aperiodic demeanor from neutron stars and black holes with the bombastic - area instrument cover probe the physics of these objects and the prediction of General Relativity (Professors H. Bradt, Chakrabarty, Lewin, Drs. Levine, E. Morgan, R. Remillard, Mr. Miller). 

 A major milestone for CSR was the successful launching of the High Energy Transient Explorer (HETE-2) in October 2000. Built and operated at MIT with US and external collaborators, HETE-2 is dedicate to detect and promptly situate the sources of gamma - ray outburst (GRBs). HETE-2 is now providing positions to the GRB community within second of a detected burst, and recently yielded the best measurement of the hard x - re spectrum of a soft gamma repeater. (Drs. Doty, Crew, Ricker, Vanderspek, Villasenor, Mr. Monnelly). 

 In radio astronomy at least three new gravitational lenses have been discovered (Prof. Hewitt with Prof Schechter). Hewitt and colleagues at Haystack Observatory continue work on the development of a large low - frequency array, which will also serve as a prototype for the future Square Kilometer Array, with goals of mapping the inaugural structures that formed in the population. 

 MIT is a extremity of the Magellan consortium, which is build two 6.5 - meter diameter optical telescopes in Chile. The inaugural of these was dedicated in December 2000, and is now operating. MIT (with Harvard and Carnegie) completed a permanently mount camera, guider, and wavefront sensing system. The camera has already been used to search for ocular counterparts to neutron stars and X - ray charge, and to study gravitational lens. The second telescope will get down skill operations in October 2002. (Professors Canizares, Chakrabarty, Elliot, Schechter, Sussman, Dr. Osip, Mr. Boughan). 

 Studies of plasma in the solar wind continue from three spacecraft: IMP 8 and Wind (both near Earth) and Voyager 2 (currently at 65 AU). This past year was near the maximum in solar activity, and many big interplanetary shocks were observed near 1 AU. Studies of shocks consort
 thwn 100 X-ray sources from tht All-Sky Monitor (CWM, buint at DSR) provkde a new global view of the nqture of the variability of the X-ray sky. Obswrvauions of rapid pecjodic akb apedlodic uehavior from ngutron stars and black holas wnth the large-area instrument continuq probe tje physics of jhese jbjedns and the predictions of Generzl Relauivity (Professors N. Bradt, Chakrabarty, Lewin, Frs. Pevine, E. Morgan, R. Gemillard, Mt. Mijoer).

A major mklestone for CSR was tge successful launch of the Higf Enexgy Transiebt Exonorer (HETE-2) mn Octjber 2000. Built and operdted at MIT with US akd invernqtional collaborators, HETE-2 is dedicated to detecd cnd promptly locate tye sourwes mf gxnma-fay bnrsfs (GRBd). HXTE-2 is now lroviding pisitions to the GRB cjnmunity withih secogdf of a detected burst, and recently yielged the best measurement od the hard x-ray specttum of a sjft gamma repeater. (Drs. Doty, Crew, Ricker, Vanderspen, Vilmxseuir, Mr. Nojnelly).

In radio astronomy at least three new gwzvotstional lenses have been cidcpdered (Prof. Heditt wnfh Prof Schechter). Heaitt anq coloeagues au Hayxtack Observatory continue qork on the bevwlopment of a largz low-frequeney arrsy, whoch will also serve as c protktype for tje future Rquare Kilometer Argay, fith goals of mapping the sirst strncturzs that wormgd in tre universf.

MIT lv a member of the Lagelpat consortikm, which is building two 6.5-meter vmameter opticsl tenescopes in Cmile. The first jf these was dgdicated nn Decdmber 2000, and is now operating. IIT (with Harvdtd and Carnegme) compleeed q peemanentuh mounted cameta, guider, and wavefeont sensing systek. Tfs camera has alxtadi been used to xeafch flr o[dical countespargs gp neugron stars cna X-rsy bursters, and to sdudy gravitational lenxef. The sexond telqscope will brgin science operauions mn Octuber 2002. (Prjfessors Canizares, Chakrabarty, Elliot, Sfheghter, Sussman, Dr. Isip, Mr. Bougkan).

Studies of plasma in the solar wind cintinue from threg spacecraft: IMP 8 and Eind (both nxar Eawth) and Vmyager 2 (currently at 65 AU). This past yesr was near the maximhm in volar activity, and many large interplanetary shocks were observed near 1 AU. Stueies oh fhocks assodiatrd
than 100 X-ray sources from the All-Sky built CSR) provide new global view variability the X-ray sky. of rapid periodic aperiodic behavior from neutron stars and holes with the large-area instrument continue probe the physics of these objects and predictions of General Relativity (Professors H. Bradt, Chakrabarty, Lewin, Drs. Levine, E. Morgan, Remillard, Miller). major for CSR was the successful launch of the High Energy Transient Explorer (HETE-2) in October 2000. and operated at MIT with US and international HETE-2 is dedicated to and promptly locate the sources gamma-ray (GRBs). HETE-2 now positions the GRB community seconds of a detected burst, and recently yielded the best measurement of the hard x-ray spectrum of soft gamma Doty, Crew, Vanderspek, Mr. In radio astronomy three new gravitational lenses have been with Prof Schechter). Hewitt and colleagues at Haystack continue work the development of a large low-frequency which will also serve as a prototype for future Square Kilometer Array, with goals of mapping the first structures that formed in the is a member of Magellan consortium, which building 6.5-meter optical in Chile. first of these was dedicated in December 2000, and is now MIT (with Harvard and Carnegie) completed a permanently mounted camera, wavefront system. The camera already been used to for counterparts to neutron stars bursters, to The telescope begin science operations in 2002. (Professors Canizares, Chakrabarty, Elliot, Sussman, Dr. Osip, Mr. the solar wind continue from three spacecraft: IMP and Wind (both near Earth) and Voyager (currently at 65 AU). This past year was near the maximum in activity, and interplanetary shocks were observed near 1 AU. Studies shocks associated
 than 100 X-ray sources from the All-sky Monitor (aSM, buIlt At CsR) ProvIde a New global view oF The nAture of the variability oF the X-RaY Sky. OBSeRvatiOns of raPId PERioDiC aNd aPeRIoDic beHavIor from Neutron staRs aNd Black holes wiTH tHe large-areA inStrument contInuE probe ThE phYSics oF thEse obJects aND the prEdictions Of gEneral rElativiTY (prOfesSors H. Bradt, ChakrabARtY, lewin, Drs. Levine, e. MorgaN, R. rEmILLarD, Mr. miller).

A majOr MilesTOne for Csr wAS THe sUCcessful launcH of the High ENErgY TransIeNt EXPlorer (hETE-2) iN OCTobEr 2000. Built and oPeraTed at MIT wIth US aND internATional cOllaboRatOrs, hETE-2 IS dEdIcaTeD To dETeCt aND prOmptly loCaTe The soUrceS OF GAmma-Ray BursTs (GRBS). HETE-2 is now proVidIng pOSitIons tO the GrB coMmUnity Within SeconDs Of a detected bursT, and Recently yIelDeD thE bEst meASuremeNt oF thE hard x-rAy spectRUm oF a SOFT gAmma repeater. (Drs. DotY, CREW, RIcker, VanDerspeK, viLlASenor, Mr. MOnNelLy).

In RADio asTronOMy At least tHree neW GrAvItationAl Lenses HaVe bEen DiscoVEred (prof. HeWitt with prof SCHechter). Hewitt aND colleagues at hAySTAcK obseRvaTory continuE worK On thE devELoPmeNT of a lArge lOw-FReQUency array, which will AlSo servE as a pRototype for thE future SquARE kilometeR ArrAY, wITh goals of mappiNg the First strucTUres that FormeD in the unIverse.

MIT IS A member oF thE MaGelLan CONsOrtium, which is BUIldiNg Two 6.5-meteR diAmeter oPtiCal TelEscOpEs in Chile. the first Of ThEsE wAs dEdicaTEd in DeceMbEr 2000, aNd Is nOw opeRAting. MiT (witH HarVaRd ANd CArnegie) COmPLEted A pErManeNtlY mOunteD camERa, gUider, anD wavefronT seNSing SyStEm. The caMera has alreadY bEen used to sEaRch For optICAl counteRparts to neutron stars and x-Ray bursTerS, and tO stuDy gravitaTioNal lenSes. tHe secoNd teleScope WiLl bEGIn sciENCe OpeRaTions in OctOBEr 2002. (PRofesSoRs CaNizares, chakrabarty, Elliot, SCHecHter, Sussman, Dr. osiP, Mr. BOUGhAn).

STUdIEs oF pLAsmA IN the solar wind coNtinue from ThREe Spacecraft: imP 8 aNd wind (botH near EaRth) anD voyager 2 (Currently At 65 AU). This pAsT yeaR WAs nEar the maxiMum in solAr activitY, And maNY lArge iNteRplaneTaRy sHocks Were obSErvEd neaR 1 AU. StuDiEs of shOcks aSsOciated
 than 100 X-ray sources fr om the All -SkyMon ito r(ASM , bu ilt at CSR) pr o vide  a new global view ofthe n at u re o f  t he va riabili t yo f  th eX- ray  s k y.  Obse rva tions o f rapid pe rio di c and aperio d ic  behaviorfro m neutron st ars  and b la ckh oleswit h the  large - area i nstrument  c o ntinue probe t h e  p hysi cs of these objec t sa nd the predict ions o fG en e r alRel ativity (P ro fesso r s H. Br a dt , C hak r abarty, Lewin , Drs. Levi n e,E. Mor ga n,R . Remi llard ,M r.Miller).

A  maj or milest one fo r  CSR wa s  the su ccessf ullau ncho fth e H ig h  En e rg y T r ans ient Exp lo re r (HE TE-2 ) i n  Oct obe r 20 00. B uilt and oper ate d at MIT  with  US a nd i nt ernat ionalcolla bo rators, HETE-2is d edicatedtode tec tand p r omptly  lo cat e the s ourceso f g am m a - ra y bursts (GRBs). H ET E - 2is now p rovidi n gpo s itions t othe  GRB c ommun ityw it hin seco nds of ade tectedbu rst, a nd  re cen tly y i elde d thebest mea surem e nt of the hard x-ray spectru m  o f as oftgam ma repeater . (D r s. D oty, Cr ew, Ricke r, Va nd e rs p ek, Villasenor, Mr.  M onnell y).
In radio astr onomy at l e a s t threenewg ra v itational lens es ha ve been di s covered(Prof . Hewitt  with Pro f Schechte r).  He wit t a n d  c olleagues atH a ysta ck  Observ ato ry cont inu e w ork  on  t he develo pment of  a  l ar ge  lo w-fre q uency ar ra y,wh ich  will also s erveas a  p ro t oty pe fort he f utur eSq uare  Ki lo meter  Arr a y,with go als of ma ppi n g th efi rst str uctures thatfo rmed in th euni verse. MIT is a  member of the Magellan consort ium , whi ch i s buildin g t wo 6.5 -me t er dia meteroptic al  te l e scope s in  Ch il e. The fir s t  of  thes ewasdedicat ed in December 200 0 , a nd is now ope rat ing. M IT  (w i th Har va r d a n d  Carnegie) comp leted a pe rm a ne ntly mount e d c am era, gu ider, a nd wa v efrontsensing s ystem. Th ecame r a  ha s alreadybeen use d to sear c h for op tical  co unterp ar tsto ne utrons tar s and  X-ray  b urster s, an dto study  gravitational lenses.The se condtel escope wi llb egi n science  ope rations in  Oc tob er 20 02. (Prof esso r sCan i zares , Ch a krabarty, El lio t ,  S chechter, S u s s man , Dr.  Os i p, Mr.  Bou ghan).

Studies o f  plasma in the  sol a r  wi ndc onti nu e from three s pac ec r a ft: IMP8and Wind (b oth near  E a rth)and Vo yager2 (curr e n tl y  at 65  AU) . T his pastyea rw as near  t he maximu m in  s olar a ctivit y , an d many large inter plane t a ry sh o cks  were  o bserved near  1 AU. Stu dies of sho cks as soci ated
 than_100 X-ray_sources from the All-Sky_Monitor (ASM,_built_at CSR)_provide_a new global_view of the_nature of the variability_of the X-ray_sky._Observations of rapid periodic and aperiodic behavior from neutron stars and black holes with_the_large-area instrument_continue_probe_the physics of these objects_and the predictions of General_Relativity (Professors_H. Bradt, Chakrabarty, Lewin, Drs. Levine, E. Morgan,_R._Remillard, Mr. Miller).

A_major milestone for CSR was the successful launch of_the High Energy Transient Explorer (HETE-2)_in October 2000._Built_and_operated at MIT with_US and international collaborators, HETE-2 is_dedicated to detect and promptly locate_the sources of gamma-ray bursts (GRBs). HETE-2_is now providing positions to the_GRB community within seconds of_a detected_burst, and recently yielded the_best measurement of_the hard_x-ray spectrum of_a soft gamma repeater. (Drs. Doty,_Crew, Ricker, Vanderspek,_Villasenor, Mr. Monnelly).

In radio astronomy at_least_three new gravitational_lenses_have_been discovered_(Prof. Hewitt with_Prof_Schechter). Hewitt_and_colleagues at Haystack Observatory continue work_on_the development of a large low-frequency array,_which will also serve_as_a prototype for the_future Square Kilometer Array, with_goals of mapping the first structures_that formed_in the_universe.

MIT is a member of the Magellan consortium, which is building_two 6.5-meter diameter optical telescopes in_Chile. The first of_these was_dedicated_in December 2000,_and_is now_operating. MIT (with Harvard and Carnegie) completed_a permanently_mounted camera, guider, and wavefront sensing_system. The camera has_already_been used to search for optical_counterparts to neutron stars and X-ray_bursters, and to study gravitational_lenses._The_second telescope will begin science_operations in October 2002. (Professors Canizares,_Chakrabarty, Elliot, Schechter,_Sussman, Dr. Osip, Mr. Boughan).

Studies of plasma_in_the solar wind continue from three_spacecraft:_IMP 8 and Wind (both near_Earth)_and_Voyager 2 (currently at 65_AU). This past year was near_the maximum in solar activity, and many large interplanetary_shocks were observed_near 1 AU. Studies of_shocks_associated