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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"

32767 results found.

  1. GRB 251005C: PRIME J-band upper limit
  2. Swift GRB 251007B: Global MASTER-Net observations report
  3. GRB 251007A: Glowbug gamma-ray detection
  4. GRB 251007B: SVOM/C-GFT upper limit
  5. Swift GRB 251007A: Global MASTER-Net observations report
  6. GRB 251007B: SVOM detection of a faint burst
  7. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  8. GRB 251005B: Glowbug gamma-ray detection
  9. EP251003a: LCO and VST fading optical counterpart
  10. GRB 251006B/EP251006a: SVOM/VT optical candidate
  11. GRB 251006B/EP251006a: EP-FXT follow-up observation
  12. GRB 251006B: SVOM/GRM observation
  13. GRB 251006B: COLIBRÍ optical upper limit
  14. GRB 251006B/EP251006a: EP-WXT detection
  15. GRB 251005C: SVOM/VT optical fading
  16. GRB 251005C: SVOM/GRM observation of a likely short GRB
  17. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  18. Fermi GRB 251006B: Global MASTER-Net observations report
  19. GRB 251006A (short): Glowbug gamma-ray detection
  20. GRB 251005C: COLIBRÍ optical observations
  21. Fermi GRB 251006A: Global MASTER-Net observations report
  22. GRB 251005C: VLT/X-shooter Imaging
  23. GRB 251003A: LAST optical observations
  24. GRB 251002A: LAST optical observations
  25. GRB 251005C: SVOM/VT optical candidate
  26. GRB 251005C: AstroSat CZTI detection
  27. GRB 251005C: Swift/UVOT Upper Limits
  28. GRB 250902A: MSU cubesats detection
  29. GRB 251005C: Fermi GBM Observation
  30. Swift GRB 251005A: Global MASTER-Net observations report
  31. GRB 251005C: GOTO optical upper limits
  32. GRB 251002A: Mondy/AZT-33IK optical observations
  33. GRB 251002A: Insight-HXMT detection
  34. GRB 251002A: Insight-HXMT detection
  35. GRB 251003A: J-band detection with WINTER
  36. GRB 251002A: NIR observations with WINTER
  37. Fermi GBM Sub-Threshold Detection of GRB 250910A
  38. GRB 251003A: Swift-BAT refined analysis
  39. GRB 251001B: NIR observations with WINTER
  40. GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  41. GRB 251003A: Swift/UVOT Upper Limits
  42. GRB 251002A: Swift/UVOT detection
  43. GRB 251001A: AstroSat CZTI detection
  44. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  45. GRB 251003A: COLIBRÍ photometric redshift
  46. GRB 251003A: GOTO detection of the optical counterpart
  47. GRB 251002A: Fermi GBM Observation
  48. GRB 251002A: GOTO detection of optical counterpart
  49. GRB 251001C: SVOM/GRM observation
  50. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  51. GRB 251002A: AKO Early Optical Afterglow Detection
  52. GRB 251003A: GTC/OSIRIS+ spectroscopic redshift z = 4.412
  53. GRB 251003A: Kilonova-Catcher optical afterglow detection
  54. GRB 251002A: Swift-XRT afterglow detection
  55. GRB 251001B: AbAO optical upper limit
  56. GRB 251002A: Kilonova-Catcher optical afterglow detection
  57. GRB 251002A: AbAO optical observations
  58. GRB 251002A: SVOM/COLIBRÍ (FM-GFT) optical observations
  59. GRB 251001C: CALET Gamma-Ray Burst Monitor detection
  60. GRB 251002A: J band observations by SYSU 80cm infrared telescope
  61. GRB 251002A: OHP/T193 MISTRAL optical afterglow detection
  62. GRB 251002A: VLT/X-shooter spectroscopic redshift z = 2.178
  63. GRB 251002A: EP-FXT counterpart detection
  64. GRB 251003A: LCOGT Optical Detection
  65. GRB 251003A: COLIBRÍ optical detection of the fading afterglow
  66. Fermi/SVOM GRB 251002A : MASTER OT earlier detection in 2 polarization filters
  67. GRB 251002A: BOOTES-6 early optical detection
  68. GRB 251002A: SAO RAS optical observations
  69. GRB 251002A: ULL-ASTRO-MASTER early detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  70. GRB 251002A: FRAM-ORM afterglow detection
  71. GRB 251002A: LCO optical observation
  72. GRB 251002A: SVOM/VT optical observation
  73. GRB 251001B: Swift-BAT refined analysis
  74. GRB 251001A: SVOM/GRM observation
  75. GRB 251001A: Insight-HXMT detection
  76. GRB 251001B: Swift/UVOT Detection
  77. GRB 251001B: COLIBRÍ optical observations
  78. GRB 251001B: GTC/OSIRIS+ spectroscopic redshift z = 2.162
  79. GRB 251001B: SVOM/VT optical observation
  80. GRB 251001B: NOT optical observations
  81. Swift GRB 251001B: Global MASTER-Net observations report
  82. GRB 251001B: Fermi GBM Observation
  83. GRB 251001B: Further GOTO observations of optical counterpart.
  84. GRB 251001B: LCOGT Optical Observations
  85. GRB 251001B: TRT optical afterglow detection and potential host galaxy
  86. GRB 251001B: GOTO optical counterpart detection
  87. GRB 250910A / EP250910a: VLT limits on the possible associated supernova
  88. LIGO/Virgo/KAGRA S250830bp: SOAR spectroscopy of two DESGW candidates
  89. LIGO/Virgo/KAGRA S250818k: further MeerKAT monitoring
  90. GRB 250910A / EP250910a: VLT/X-shooter host galaxy redshift z = 0.592
  91. GRB 250925A: MAO/AZT-22 optical observations
  92. Fermi GRB 250929A: Global MASTER-Net observations report
  93. GRB 250926A: CALET Gamma-Ray Burst Monitor detection
  94. LIGO/Virgo/KAGRA S250929c: Updated Sky localization
  95. GRB 250925A: Mondy I-band optical observations
  96. GRB 250916A: SVOM/VT optical observation
  97. LIGO/Virgo/KAGRA S250929c: Identification of a GW compact binary merger candidate
  98. LIGO/Virgo/KAGRA S250927cy: Updated Sky localization
  99. LIGO/Virgo/KAGRA S250927ck: Updated Sky localization
  100. Fermi-LAT Gamma-ray Observations of IceCube-250926A

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