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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').
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"

20509 results found.

  1. GRB 251005C: PRIME J-band upper limit
  2. GRB 251007B: SVOM/C-GFT upper limit
  3. GRB 251007B: Swift detection of a burst
  4. GRB 251007A: Swift detection of a burst with an optical counterpart
  5. GRB 250702B/EP250702a: JWST/NIRCam Observations
  6. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  7. GRB 251006B: SVOM/GRM observation
  8. GRB 251006B: COLIBRÍ optical upper limit
  9. GRB 251006B/EP251006a: EP-WXT detection
  10. GRB 251005C: SVOM/VT optical fading
  11. GRB 251005C: SVOM/GRM observation of a likely short GRB
  12. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  13. GRB 251005C: COLIBRÍ optical observations
  14. Fermi GRB 251006A: Global MASTER-Net observations report
  15. GRB 251005C: VLT/X-shooter Imaging
  16. GRB 251003A: LAST optical observations
  17. GRB 251002A: LAST optical observations
  18. GRB 251005C: Swift/UVOT Upper Limits
  19. GRB 251005C: Swift-XRT refined Analysis
  20. GRB 251005C: Enhanced Swift-XRT position
  21. GRB 251005C: Swift detection of a burst
  22. GRB 251002A: Mondy/AZT-33IK optical observations
  23. EP251003a: Einstein Probe detection of an X-ray transient
  24. GRB 251003A: J-band detection with WINTER
  25. GRB 251002A: NIR observations with WINTER
  26. GRB 251001B: NIR observations with WINTER
  27. GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  28. GRB 251003A: Swift/UVOT Upper Limits
  29. GRB 251002A: Swift/UVOT detection
  30. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  31. GRB 251002A: GOTO detection of optical counterpart
  32. GRB 251001C: SVOM/GRM observation
  33. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  34. GRB 251003A: Enhanced Swift-XRT position
  35. GRB 251002A: AKO Early Optical Afterglow Detection
  36. GRB 251003A: Kilonova-Catcher optical afterglow detection
  37. GRB 251002A: Swift-XRT afterglow detection
  38. GRB 251001B: AbAO optical upper limit
  39. GRB 251002A: Kilonova-Catcher optical afterglow detection
  40. GRB 251002A: AbAO optical observations
  41. GRB 251002A: SVOM/COLIBRÍ (FM-GFT) optical observations
  42. GRB 251002A: J band observations by SYSU 80cm infrared telescope
  43. GRB 251002A: OHP/T193 MISTRAL optical afterglow detection
  44. GRB 251002A: VLT/X-shooter spectroscopic redshift z = 2.178
  45. GRB 251003A: LCOGT Optical Detection
  46. GRB 251003A: COLIBRÍ optical detection of the fading afterglow
  47. GRB 251003A: Swift detection of a burst
  48. GRB 251002A: SAO RAS optical observations
  49. GRB 251002A: ULL-ASTRO-MASTER early detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  50. GRB 251002A: LCO optical observation
  51. GRB 251002A: SVOM/VT optical observation
  52. GRB 251002A: SVOM detection of a burst
  53. GRB 251001A: SVOM/GRM observation
  54. GRB 251001B: Swift/UVOT Detection
  55. GRB 251001B: COLIBRÍ optical observations
  56. GRB 251001B: Swift-XRT refined Analysis
  57. GRB 251001B: SVOM/VT optical observation
  58. GRB 251001B: NOT optical observations
  59. GRB 251001B: Enhanced Swift-XRT position
  60. GRB 251001B: LCOGT Optical Observations
  61. GRB 250930A: SVOM/GRM observation
  62. GRB 251001B: TRT optical afterglow detection and potential host galaxy
  63. GRB 251001B: Swift detection of a burst
  64. GRB 250910A / EP250910a: VLT limits on the possible associated supernova
  65. LIGO/Virgo/KAGRA S250818k: further MeerKAT monitoring
  66. GRB 250925A: MAO/AZT-22 optical observations
  67. GRB 250925A: Mondy I-band optical observations
  68. LIGO/Virgo/KAGRA S250929c: Identification of a GW compact binary merger candidate
  69. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  70. GRB 250924A: SVOM/GRM observation
  71. GRB 250925A: Swift-XRT refined Analysis
  72. LIGO/Virgo/KAGRA S250927cy: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S250927ck: Identification of a GW compact binary merger candidate
  74. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  75. GRB 250920C: ULL-ASTRO-MASTER early detection of the optical afterglow with LCO 40-cm telescope at Siding Spring Observatory
  76. GRB 250925A: Mondy and AbAO optical observations
  77. GRB 250925A: SVOM/GWAC-F60A upper limit
  78. GRB 250925A/EP250925a: EP-WXT detection
  79. GRB 250926A: DDOTI Optical Observations and Spatial Coincidence with the Orion Nebula
  80. GRB 250925A : MITSuME Akeno optical upper limits
  81. GRB 250925A: JinShan optical observations
  82. GRB 250919A / EP250919a: Global MASTER Net before, during and after trigger optical observations
  83. GRB 250925A: COLIBRÍ optical photometry of the afterglow
  84. GRB250925A: Liverpool Telescope optical observations
  85. GRB 250925A: NOT optical afterglow candidate
  86. GRB 250925A: Leavitt Observatory optical upper limit
  87. GRB 250925A: Enhanced Swift-XRT position
  88. GRB 250925A: GROWTH-India Telescope Upper Limits
  89. GRB 250922A: SVOM/GRM observation
  90. GRB 250924A: 1.6m Mephisto optical upper limits
  91. GRB 250924A: SAO RAS optical observations
  92. GRB 250914A: AstroSat CZTI detection
  93. GRB 250920B: AstroSat CZTI detection
  94. GRB 250924A: SVOM/VT optical observation
  95. GRB 250924A: Swift/UVOT Detection
  96. GRB 250924A: Enhanced Swift-XRT position
  97. GRB 250924A: J-band detection with WINTER
  98. GRB 250924A: GROWTH-India Telescope Upper Limits
  99. GRB 250924A: Mondy optical observations, afterglow fading
  100. GRB 250924A: Kilonova-Catcher optical afterglow detection

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