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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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').
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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"

18515 results found.

  1. GRB 250329B: Swift/UVOT Upper Limit
  2. GRB 250329A: Swift/UVOT Upper Limit
  3. GRB 250327B: Swift/UVOT Detection
  4. GRB 250327A: Swift/UVOT Upper Limits
  5. GRB 250331E: SVOM/GRM observation
  6. GRB 250327B: Kilonova-Catcher Observations
  7. GRB 250331D: Fermi GBM observation
  8. GRB 250331C: Swift/UVOT Upper Limits
  9. GRB 250331B: Swift/UVOT Upper Limits
  10. GRB 250328A: AbAO AS-32 Optical Observations
  11. GRB 250219A: NOT candidate host galaxy detection
  12. GRB 250330B: SVOM/GRM observation of a short burst
  13. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  14. GRB 250331C: Enhanced Swift-XRT position
  15. GRB 250331B: Enhanced Swift-XRT position
  16. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  17. GRB 250330A: VLT/FORS2 Afterglow Detection
  18. GRB20250327B: 45th Parallel Observatory upper limit
  19. GRB 250328A: Swift/UVOT Detection
  20. GRB 250328A: Swift-XRT refined Analysis
  21. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  22. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  23. GRB 250331C: Swift detection of a burst
  24. GRB 250331B: Swift detection of a burst
  25. GRB 250330A: BOOTES-7 early optical upper limit
  26. GRB 250330A: Swift/UVOT Upper Limits
  27. GRB 250330A: Swift-XRT afterglow detection
  28. GRB 250328A: 1.6m Mephisto optical observations
  29. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  30. GRB 250330A: VLT/FORS2 Optical Observations
  31. GRB 250329B: Swift-XRT afterglow detection
  32. GRB 250330A: Swift detection of a burst
  33. GRB 250329B: SVOM/C-GFT optical upper limit
  34. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  35. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  36. GRB250329A: REM optical afterglow detection
  37. GRB 250329A: Swift-XRT afterglow detection
  38. GRB 250328A: SVOM/VT optical observation
  39. GRB 250329A: Fading optical counterpart detection by LCO.
  40. GRB 250328A: SVOM/C-GFT optical upper limit
  41. GRB 250328A: SVOM/COLIBRÍ (F-GFT) optical afterglow candidate
  42. GRB 250329A: SVOM/VT optical counterpart confirmation
  43. GRB 250329A: SVOM detection of a burst
  44. GRB 250329A: SVOM/COLIBRÍ (F-GFT) Detection of a Bright Optical Counterpart Candidate
  45. GRB 250327B: J-band observations with WINTER
  46. GRB 250327B: LCO optical counterpart detection
  47. EP250302a: SPI-ACS/INTEGRAL Upper Limit
  48. GRB 250327B: CrAO and SAO RAS Optical Observations
  49. GRB 250327b: Liverpool Telescope optical observations
  50. GRB 250322A: GRANDMA/TNOT optical upper limits
  51. GRB 250327A: SVOM/VT upper limits on the XRT position
  52. LIGO/Virgo/KAGRA S250328ae: Identification of a GW compact binary merger candidate
  53. GRB 250327B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  54. GRB 250327B: Las Cumbres optical counterpart detection
  55. GRB 250327B: 1.6m Mephisto optical observations
  56. GRB 250327B: SVOM/VT optically bright counterpart
  57. GRB 250327B: SAO RAS optical candidate
  58. GRB 250327B: SVOM detection of a burst
  59. GRB 250327A: J-band observations with WINTER
  60. GRB 250327A: SVOM/VT optical candidate
  61. FRB 20250316A: Pan-STARRS r and i-band imaging and photometry
  62. GRB 250327A: DDOTI Optical Observations
  63. GRB 250327A: COLIBRÍ optical upper limit
  64. IPN triangulation of GRB 250322B
  65. LIGO/Virgo/KAGRA S250326y: Identification of a GW compact binary merger candidate
  66. EP250321a: Mondy AZT-33IK Continued Optical Observations
  67. Swift follow-up observations of FRB250316A and EP J120944.2+585060
  68. GRB 250322A: third epoch of NOT optical observations
  69. GRB 250321B: ISON-Kitab RC-36 Optical Upper Limit
  70. FRB 250316A: NOT optical upper limit for the X ray source EP J120944.2+585060
  71. GRB 250322A: further NOT optical observations
  72. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  73. GRB 250322A: Swift/UVOT Upper Limits
  74. EP250324A: COLIBRÍ/DDRAGO Optical Observations
  75. FRB 250316A: COLIBRÍ/DDRAGO Optical follow up of the X ray source EP J120944.2+585060
  76. GRB 250321B: Swift-XRT observations
  77. EP250321a: TNOT Observation of Optical Counterpart
  78. FRB 250316A: DDOTI Continued Optical Observations (Third Epoch)
  79. GRB 250322B: AstroSat CZTI detection of a bright long burst
  80. GRB 250322A: VLT optical observations
  81. GRB 250322A: VLT near-infrared observations
  82. FRB 250316A: DDOTI Continued Optical Observations
  83. GRB 250322A: NOT optical upper limits
  84. GRB 250322A: Enhanced Swift-XRT position
  85. GRB 250321B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  86. FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
  87. EP250321a: Liverpool Telescope optical follow-up
  88. EP250321a: Mondy AZT-33IK Optical Observations
  89. GRB 250322A: Swift detection of a short burst
  90. FRB 20250316A: detection of a candidate associated X-ray source EP J120944.2+585060 by Einstein Probe
  91. EP250321a: refined analysis of the EP-WXT and EP-FXT observations
  92. EP250321A: COLIBRÍ Continuing Optical Observations
  93. EP250321a: WFST optical observations
  94. EP250321a: Xinglong 216 decaying optical observations
  95. GRB 250321A: Swift-XRT refined Analysis
  96. EP 250321A: Optical counterpart detection by LCO.
  97. EP250321a: Kinder optical follow-up observations
  98. GRB 250321A: Swift/UVOT Upper Limits
  99. GRB 250320B: SVOM/GRM observation of a long burst
  100. EP250321a: LCO optical counterpart detection

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