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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

5547 results found.

  1. Integral GRB240929.83: Global MASTER-Net observations report
  2. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  3. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  4. GRB 240926A: SVOM/GRM observation
  5. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  6. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  7. EP240919a / GRB 240919A: SVOM/VT upper limit
  8. EP240918b and EP240918c: EP-FXT follow-up observations
  9. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  10. GRB 240905B: VZLUSAT-2 detection
  11. EP trigger ID 01709059262: correction to the observation start time and source localization
  12. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  13. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo S240919bn: GOTO optical upper limits
  16. GRB 240918B: AstroSat CZTI detection
  17. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  18. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  19. EP240919a: EP-FXT follow-up observation update
  20. EP240913A/GRB 240913C: AbAO optical upper limit
  21. EP240919a / GRB 240919A: Mondy optical upper limit
  22. EP240913a/GRB 240913C: 1.6m Mephisto observations
  23. EP240918a: SVOM/VT upper limit
  24. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  25. GRB 240919A / EP240919a: SVOM/GRM observation
  26. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  27. EP EP240919a: Global MASTER-Net observations report
  28. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  29. EP240919a: NOT and Gemini optical observations
  30. EP240919a: GOTO optical upper limits
  31. EP240919a: JinShan optical upper limits
  32. EP240919a is likely a GRB event
  33. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  34. EP240919a: EP-WXT detection of a fast X-ray transient
  35. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  36. EP240918a: EP observation update
  37. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  38. EP240918a: Swift-XRT observation
  39. Fermi GRB 240918A: Global MASTER-Net observations report
  40. EP EP240918a: Global MASTER-Net observations report
  41. EP240918a: JinShan optical upper limits
  42. EP240918a: YAHPT Optical Upper Limit
  43. EP240918a: GMG Optical Upper Limit
  44. GRB 240916A: GRBAlpha detection
  45. GRB 240914B: GRBAlpha detection
  46. EP240918a: an X-ray transient detected by Einstein Probe
  47. GRB 240916A: NOT optical observation
  48. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S240915b: NED Galaxies in the Localization Volume
  51. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  52. GRB 240914B: Fermi GBM Final Localization
  53. The EP-WXT triggers 01709047257 and 01709047278 are not real sources
  54. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  55. EP EP240913a: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  57. EP240913a: VLT/HAWK-I near-infrared upper limits
  58. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  60. EP240913a / GRB 240913C INTEGRAL SPI ACS LIGHT CURVE
  61. GRB 240913C: Joint location by ETJASMIN
  62. GRB 240914B: AstroSat CZTI detection
  63. EP240913A / GRB 240913C: AstroSat CZTI detection
  64. GRB 240914A: SVOM/GRM observation
  65. GRB 240910A: SVOM/VT optical observations
  66. EP240913a: NOT optical upper limits
  67. EP240913a: JinShan optical upper limits
  68. EP240913a: ESO-NTT optical observations
  69. GRB 240914A: ESO-NTT optical observations
  70. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  71. GRB 240914B: BALROG localization (Fermi Trigger 747990592 / GRB 240914298)
  72. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  73. GRB 240905E: further NOT optical observations
  74. EP240913a: A GRB Event
  75. EP240913a: EP-WXT detection of a fast X-ray transient
  76. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  77. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  78. Fermi trigger No 747920561: Global MASTER-Net observations report
  79. GRB 240912A: SVOM/GRM observation
  80. Fermi GRB 240913A: Global MASTER-Net observations report
  81. GRB 240912A: J-band observations with WINTER
  82. Swift GRB 240912A: Global MASTER-Net observations report
  83. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  84. GRB 240912A: NOT optical spectroscopy
  85. GRB 240912A: Redshift from OSIRIS+/GTC
  86. GRB 240910A: Redshift from OSIRIS+/GTC
  87. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  88. GRB 240910A: GOTO candidate optical counterpart
  89. GRB 240825A: 7DT Optical Upper Limit
  90. GRB 240905E: SVOM/VT optical observations
  91. GRB 240910A: GRBAlpha detection
  92. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  93. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  94. GRB 240910A: SVOM/GRM observation
  95. EP240908a: Mondy and AbAO follow-up observations
  96. EP240908a: Updates on the WXT detection result around the trigger time
  97. Fermi GRB 240910A: Global MASTER-Net observations report
  98. EP EP240908a: Global MASTER-Net observations report
  99. Fermi trigger No 747553301: Global MASTER-Net observations report
  100. EP240908a: TRT optical upper limit

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