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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.

Advanced Search Examples (click to copy):

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

36384 results found.

  1. GRB 250219A: Swift-XRT observations
  2. LIGO/Virgo/KAGRA S250206dm: Upper limits from MSU cubesats observations
  3. GRB 250219A: Swift ToO observations
  4. GRB 250219A: SVOM detection of a burst
  5. Konus-Wind detection of GRB 250215A / EP250215a
  6. GRB 250217C: Swift-XRT observations
  7. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  8. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  9. GRB 250217C: SVOM/GRM observation
  10. GRB 250217C: Tiled Swift observations
  11. GRB 250217C: Fermi GBM Observation
  12. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  13. IPN triangulation of GRB 250217C (short)
  14. GRB 250213A: Swift-XRT observations
  15. LIGO/Virgo/KAGRA S250206dm: AZT-33IK Target Optical Observations
  16. GRB 250216A: AstroSat CZTI detection
  17. GRB 250217C: AstroSat CZTI detection of a short burst
  18. Fermi GRB 250217C: Global MASTER-Net observations report
  19. GRB 250217C: Fermi GBM Final Real-time Localization
  20. LIGO/Virgo/KAGRA S250206dm: observation in AbAO, optical transient near NED/GLADE+ galaxy WISEA J021210.14+514821.7
  21. Fermi GRB 250217A: Global MASTER-Net observations report
  22. GRANDMA/OPD observations of GRB250215A
  23. GRB 250217B: Fermi GBM Final Real-time Localization
  24. GRB 250217A: Fermi GBM Final Real-time Localization
  25. Fermi GRB 250216A: Global MASTER-Net observations report
  26. GRB 250215A / EP250215a: LCO detection of the afterglow
  27. GRB 250216A: Fermi GBM Final Real-time Localization
  28. GRB 250215A: Swift/UVOT Upper Limits
  29. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  30. EP250215a / GRB 250215A : GTC redshift z = 4.61
  31. GRB 250215A: Fermi GBM Observation
  32. EP250215a / GRB 250215A : NOT optical observations
  33. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  34. GRB 250215A / EP250215a: Gemini-South optical observation of a likely rebrightening
  35. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  36. GRB 250215A: Swift-XRT refined Analysis
  37. GRB 250215A: SVOM/GRM observation
  38. EP250215a / GRB 250215A: AstroSat CZTI detection
  39. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  40. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  41. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  42. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  43. Fermi GRB 250215A: Global MASTER-Net observations report
  44. GRB 250215A: Fermi GBM Final Real-time Localization
  45. GRB 250213A：SVOM/VT optical candidate
  46. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  47. Fermi GRB 250214A: Global MASTER-Net observations report
  48. GRB 250213A: Swift ToO observations
  49. GRB 250214A: Fermi GBM Final Real-time Localization
  50. GRB 250213A: SVOM detection of a burst
  51. GRB 250205A: VIRT Optical Upper Limit
  52. GRB 250205A: Leavitt Observatory optical upper limit
  53. GRB 250210A: GRBAlpha detection
  54. Fermi GRB 250212A: Global MASTER-Net observations report
  55. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  56. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  57. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  58. GRB 250211B: A long GRB detected by INTEGRAL
  59. GRB 250211A: Swift ToO observations
  60. GRB 250212A: Fermi GBM Final Real-time Localization
  61. GRB 250207A: Fermi GBM Observation
  62. GRB 250206A: Fermi GBM Observation
  63. GRB 250205A / EP250205A: radio detection with the VLA
  64. Konus-Wind detection of GRB 250207A
  65. Konus-Wind detection of GRB 250206A
  66. GRB 250210A: SVOM/GRM observation of a long burst
  67. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  68. GRB 250207A: Skynet optical afterglow observations
  69. GRB 241128A: VIRT Optical Upper Limit
  70. EP250207A: Upper limits from Fermi-GBM Observations
  71. GRB 250210A: INTEGRAL SPI-ACS detection
  72. GRB 250210A: AstroSat CZTI detection
  73. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  74. Fermi GRB 250210A: Global MASTER-Net observations report
  75. GRB 250210A: Fermi GBM Final Real-time Localization
  76. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  77. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 250204B: GRBAlpha detection
  79. GRB 250204A: GRBAlpha detection
  80. GRB 250207A: 1.3m DFOT Optical observations
  81. GRB 250206A: Swift-XRT observations
  82. GRB 250129A: GRANDMA Continued Afterglow Detection
  83. GRB 250207A: Swift-BAT refined analysis
  84. GRB 250205A: 1.3m DFOT optical upper limit
  85. GRB 250206A: Tiled Swift observations
  86. GRB 250206A: EIRSAT-1 GMOD Detection
  87. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  88. GRB 250206A: Fermi-LAT detection
  89. GRB 250207B: Swift-XRT observations
  90. GRB 250208A: Fermi GBM Final Real-time Localization
  91. GRB 250207A: Swift-XRT refined Analysis
  92. GRB 250207A: Enhanced Swift-XRT position
  93. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  94. GRB 250207A: REM IR afterglow detection
  95. GRB 250207A: FRAM-Auger optical detection
  96. GRB 250207B: Tiled Swift observations
  97. Konus-Wind detection of GRB 250204B
  98. GRB 250207A: REM optical afterglow detection
  99. GRB 250207A: Swift/UVOT Detection
  100. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation

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