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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.

Advanced Search Examples (click to copy):

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

92 results found.

  1. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  2. Fermi GRB 251214A: Global MASTER-Net observations report
  3. GRB 251211B: AstroSat CZTI detection
  4. GRB 250818B: MeerKAT Detection
  5. EP250812a: NOT, NTT, and GS observations
  6. GRB 250625A: Swift-XRT refined Analysis
  7. GRB 250520A: Gemini-South optical afterglow detection
  8. GRB 250520A: Gemini-South optical observations
  9. EP250508a: Gemini NIR upper limits
  10. GRB 250322A: Gemini-South optical observations
  11. Fermi trigger No 763933627: Global MASTER-Net observations report
  12. EP250225a: Global MASTER-Net observations report
  13. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  14. Integral GRB241215.58: Global MASTER-Net observations report
  15. GRB 241212A: AstroSat CZTI detection
  16. Fermi trigger No 754701230: Global MASTER-Net observations report
  17. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  18. GRB241105A: Gemini-South Optical Afterglow Detection
  19. EP241021a: Gemini-South detection of optical rebrightening
  20. Konus-Wind detection of GRB 241025A
  21. Fermi trigger No 749693019: Global MASTER-Net observations report
  22. GRB 240821A: Fermi GBM Observation
  23. GRB 240805B: Swift/UVOT Upper Limits
  24. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  25. GRB 240606B: Fermi GBM Observation
  26. GRB 240513A: AstroSat CZTI detection
  27. Fermi GRB 240428A: Global MASTER-Net observations report
  28. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  29. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  30. GRB 231111A: Swift detection of a burst with an optical counterpart
  31. Fermi GRB 231030B: Global MASTER-Net observations report
  32. GRB 230204B: Fermi GBM detection
  33. GRB 230102A: Fermi GBM Observation
  34. GRB221009A: Gemini-South Optical Afterglow Detection
  35. GRB 220803A: AstroSat CZTI detection
  36. IceCube Alert 220513.97: Global MASTER-Net observations report
  37. GRB 220308B: Fermi GBM detection
  38. Fermi GRB 220309A: Global MASTER-Net observations report
  39. IceCube Alert 220202.49: Global MASTER-Net observations report
  40. Fermi GRB 211212A: Global MASTER-Net observations report
  41. Fermi trigger No 653093506: Global MASTER-Net observations report
  42. Konus-Wind detection of GRB 210619B
  43. Fermi trigger No 645047470: Global MASTER-Net observations report
  44. ZTF21aayokph (AT2021lfa): Redshift from Gemini South
  45. Fermi trigger No 641601187: Global MASTER-Net observations report
  46. GRB 210102B: MAXI/GSC detection
  47. GRB 201026A: Swift/UVOT Upper Limits
  48. GRB 201006A: Swift/UVOT Upper Limits
  49. Fermi GRB 200909A: Global MASTER-Net observations report
  50. Fermi GRB 200420A: Global MASTER-Net observations report
  51. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  52. Fermi trigger No 600666048: Global MASTER-Net observations report
  53. Swift GRB191226.02: Global MASTER-Net observations report
  54. LIGO/Virgo S190814bv Global MASTER-Net observations report
  55. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  56. LIGO/Virgo S190602aq: Identification of a GW compact binary merger candidate
  57. GRB 190311A: Swift/UVOT Detection
  58. GRB 171205A: Swift-XRT refined Analysis
  59. GRB 170921A: Swift-XRT refined Analysis
  60. Konus-Wind observation of GRB 170808B
  61. GRB 170803A: Swift/UVOT Detection
  62. GRB 161219B: Swift-XRT refined Analysis
  63. GRB 161213A: POLAR Observation
  64. GRB 160525B: Swift/UVOT Detection
  65. GRB 150831A: Swift/UVOT Upper Limits
  66. Swift Trigger 646423 is GS 1354-645
  67. GRB 150530A: Swift/UVOT Upper Limits
  68. Konus-Wind observation of GRB 140329A
  69. GRB 140311A: Swift/UVOT Upper Limits
  70. GRB 130427A: Zadko observatory - Gingin optical observations
  71. GRB 110213A: Swift/UVOT refined analysis
  72. Konus-Wind observation of GRB 110205A
  73. Short GRB 110106A: MASTER OT observations
  74. GRB 101017A: Swift/UVOT Observations
  75. GRB 100802A: Swift/UVOT Possible Optical Afterglow
  76. GRB100425A: Swift/UVOT Upper Limits
  77. INTEGRAL Alert n. 5995: MASTER-Net optical observations
  78. Swift/UVOT refined analysis of GRB100117A
  79. GRB 091128: Fermi GBM detection
  80. GRB 090904B: Fermi GBM detection
  81. GRB 090815B: Fermi GBM detection
  82. GRB 090423: Fermi GBM observation
  83. Fermi Detection of GRB 081102
  84. GRB080913: Swift/UVOT Upper Limits
  85. GRB 071117: Gemini Observations
  86. Swift/UVOT refined analysis of GRB070531
  87. Konus-Wind observation of GRB 051008
  88. GRB050922B: Swift UVOT early upper limits.
  89. GRB050801: Swift/UVOT Optical and UV detections
  90. Swift/UVOT photometry of GRB050730
  91. ROTSE-III prompt optical detections of GRB 030418
  92. GRB000926 Host Galaxy Observations

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