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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"

96 results found.

  1. EP260210a: refined analysis of the EP-FXT observation
  2. GRB 260208B: Swift-XRT observations
  3. Konus-Wind detection of GRB 260131A/B
  4. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  5. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  6. Fermi GRB 251214A: Global MASTER-Net observations report
  7. GRB 251211B: AstroSat CZTI detection
  8. GRB 250818B: MeerKAT Detection
  9. EP250812a: NOT, NTT, and GS observations
  10. GRB 250625A: Swift-XRT refined Analysis
  11. GRB 250520A: Gemini-South optical afterglow detection
  12. GRB 250520A: Gemini-South optical observations
  13. EP250508a: Gemini NIR upper limits
  14. GRB 250322A: Gemini-South optical observations
  15. Fermi trigger No 763933627: Global MASTER-Net observations report
  16. EP250225a: Global MASTER-Net observations report
  17. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  18. Integral GRB241215.58: Global MASTER-Net observations report
  19. GRB 241212A: AstroSat CZTI detection
  20. Fermi trigger No 754701230: Global MASTER-Net observations report
  21. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  22. GRB241105A: Gemini-South Optical Afterglow Detection
  23. EP241021a: Gemini-South detection of optical rebrightening
  24. Konus-Wind detection of GRB 241025A
  25. Fermi trigger No 749693019: Global MASTER-Net observations report
  26. GRB 240821A: Fermi GBM Observation
  27. GRB 240805B: Swift/UVOT Upper Limits
  28. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  29. GRB 240606B: Fermi GBM Observation
  30. GRB 240513A: AstroSat CZTI detection
  31. Fermi GRB 240428A: Global MASTER-Net observations report
  32. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  33. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  34. GRB 231111A: Swift detection of a burst with an optical counterpart
  35. Fermi GRB 231030B: Global MASTER-Net observations report
  36. GRB 230204B: Fermi GBM detection
  37. GRB 230102A: Fermi GBM Observation
  38. GRB221009A: Gemini-South Optical Afterglow Detection
  39. GRB 220803A: AstroSat CZTI detection
  40. IceCube Alert 220513.97: Global MASTER-Net observations report
  41. GRB 220308B: Fermi GBM detection
  42. Fermi GRB 220309A: Global MASTER-Net observations report
  43. IceCube Alert 220202.49: Global MASTER-Net observations report
  44. Fermi GRB 211212A: Global MASTER-Net observations report
  45. Fermi trigger No 653093506: Global MASTER-Net observations report
  46. Konus-Wind detection of GRB 210619B
  47. Fermi trigger No 645047470: Global MASTER-Net observations report
  48. ZTF21aayokph (AT2021lfa): Redshift from Gemini South
  49. Fermi trigger No 641601187: Global MASTER-Net observations report
  50. GRB 210102B: MAXI/GSC detection
  51. GRB 201026A: Swift/UVOT Upper Limits
  52. GRB 201006A: Swift/UVOT Upper Limits
  53. Fermi GRB 200909A: Global MASTER-Net observations report
  54. Fermi GRB 200420A: Global MASTER-Net observations report
  55. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  56. Fermi trigger No 600666048: Global MASTER-Net observations report
  57. Swift GRB191226.02: Global MASTER-Net observations report
  58. LIGO/Virgo S190814bv Global MASTER-Net observations report
  59. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  60. LIGO/Virgo S190602aq: Identification of a GW compact binary merger candidate
  61. GRB 190311A: Swift/UVOT Detection
  62. GRB 171205A: Swift-XRT refined Analysis
  63. GRB 170921A: Swift-XRT refined Analysis
  64. Konus-Wind observation of GRB 170808B
  65. GRB 170803A: Swift/UVOT Detection
  66. GRB 161219B: Swift-XRT refined Analysis
  67. GRB 161213A: POLAR Observation
  68. GRB 160525B: Swift/UVOT Detection
  69. GRB 150831A: Swift/UVOT Upper Limits
  70. Swift Trigger 646423 is GS 1354-645
  71. GRB 150530A: Swift/UVOT Upper Limits
  72. Konus-Wind observation of GRB 140329A
  73. GRB 140311A: Swift/UVOT Upper Limits
  74. GRB 130427A: Zadko observatory - Gingin optical observations
  75. GRB 110213A: Swift/UVOT refined analysis
  76. Konus-Wind observation of GRB 110205A
  77. Short GRB 110106A: MASTER OT observations
  78. GRB 101017A: Swift/UVOT Observations
  79. GRB 100802A: Swift/UVOT Possible Optical Afterglow
  80. GRB100425A: Swift/UVOT Upper Limits
  81. INTEGRAL Alert n. 5995: MASTER-Net optical observations
  82. Swift/UVOT refined analysis of GRB100117A
  83. GRB 091128: Fermi GBM detection
  84. GRB 090904B: Fermi GBM detection
  85. GRB 090815B: Fermi GBM detection
  86. GRB 090423: Fermi GBM observation
  87. Fermi Detection of GRB 081102
  88. GRB080913: Swift/UVOT Upper Limits
  89. GRB 071117: Gemini Observations
  90. Swift/UVOT refined analysis of GRB070531
  91. Konus-Wind observation of GRB 051008
  92. GRB050922B: Swift UVOT early upper limits.
  93. GRB050801: Swift/UVOT Optical and UV detections
  94. Swift/UVOT photometry of GRB050730
  95. ROTSE-III prompt optical detections of GRB 030418
  96. GRB000926 Host Galaxy Observations

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