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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"

32692 results found.

  1. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  2. Konus-Wind detection of GRB 250113A
  3. IPN triangulation of GRB 250113A
  4. GRB 250114B: Liverpool Telescope optical upper limit
  5. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  6. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  7. GRB 250114A: LCO optical counterpart detection.
  8. GRB 250114B: OHP/T193 optical upper limit
  9. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  10. GRB 250114A: LCOGT optical afterglow i-band detection
  11. GRB 250114B : GIT optical upper limit
  12. GRB 250114B: Swift ToO observations
  13. EP250111a: SAO RAS optical upper limit
  14. EP250108a: correction to GCN 38908
  15. GRB 250113A: INTEGRAL/SPI-ACS detection
  16. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  17. GRB 250114A: REM detection of the optical and NIR counterpart
  18. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  19. GRB 250114A: LCO optical observations
  20. GRB 250114A: TRT optical observations
  21. Swift GRB 250114A: Global MASTER-Net observations report
  22. GRB 250101A: Terskol Zeiss-2000 optical observations
  23. EP250108a / AT 2025kg: SAO RAS optical observations
  24. EP241021a: SMA radio observation
  25. GRB 250107A: VZLUSAT-2 detection
  26. GRB 250109A / EP250109a: GRBAlpha detection
  27. GRB 250107D: GRBAlpha detection
  28. EP250111a: KAIT optical observations
  29. GRB 250109A / EP250109a: Mephisto optical upper limits
  30. EP250108a: Mephisto detection
  31. EP250111a: Mondy optical observation
  32. EP250108a / AT 2025kg: LCO optical observations
  33. EP250111a: Global MASTER-Net observations report
  34. EP250111a: Swift/XRT detection and fading
  35. EP250108a / AT 2025kg: Swift UVOT detections
  36. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  37. EP250108a: optical follow-up observations with the Liverpool Telescope
  38. EP250111a: NOT likely optical counterpart
  39. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  40. GRB 250101B: Fermi GBM Observation
  41. EP250108a: further NOT optical observations
  42. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  43. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  44. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  45. GRB 250108A: Swift/XRT afterglow fading
  46. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  47. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  48. Konus-Wind detection of GRB 250107C
  49. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  50. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  51. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  52. GRB 250101A: CMO RC-500 optical observations
  53. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  54. EP250108a: EP-FXT follow-up observation
  55. GRB 250109A: Fermi GBM Observation
  56. EP250108a: NOT optical observations
  57. GRB 250109a: GMG Optical Upper Limit
  58. EP250109a: Swift/UVOT non-detection
  59. Konus-Wind detection of GRB 250107D (short/hard)
  60. IPN triangulation of GRB 250107D (short/hard)
  61. IPN triangulation of GRB 250107C
  62. EP250108a: Liverpool Telescope likely optical counterpart
  63. GRB 250108B: Gemini-North likely redshift z = 2.197
  64. GRB 250108B: Swift-BAT refined analysis
  65. GRB 250108B: 1.3m DFOT upper limit
  66. GRB 250108B: REM optical/NIR upper limits
  67. GRB 250109A /EP250109a: Fermi GBM Final Localization
  68. EP250109a: SVOM/VT optical candidate
  69. EP250109a: Global MASTER-Net observations report
  70. GRB 250101A: Terskol K-800 optical observations
  71. EP250109a: GOTO optical upper limits
  72. EP250109a: Swift/XRT non-detection
  73. GRB 250108A: Swift/UVOT Upper Limits
  74. EP250108a: Global MASTER-Net observations report
  75. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  76. GRB 250108A: NOT optical upper limit
  77. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  78. Swift GRB 250108B: Global MASTER-Net observations report
  79. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  80. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  81. GRB 250103A: 1.6m Mephisto optical observations
  82. GRB 250108A:SVOM/VT optical candidate
  83. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  84. GRB 250108B: Swift/UVOT Upper Limits
  85. GRB 250108A: Swift ToO observations
  86. GRB 250107A: Fermi GBM Observation
  87. GRB 241228B: Fermi-LAT detection
  88. Fermi GRB 250107B: Global MASTER-Net observations report
  89. GRB 250107A: Swift ToO observations
  90. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  91. GRB 250106A: SVOM/VT 2nd optical deep observation
  92. GRB 250101A: J band upper limit by SYSU 80cm telescope
  93. GRB 250106A: NOT optical observations
  94. LIGO/Virgo/KAGRA S250104v: Updated Sky localization
  95. GRB 250103B: REM optical/NIR upper limits
  96. GRB 250101A: REM optical/NIR counterpart detection
  97. GRB 250106A: Swift-XRT observations
  98. GRB 250106A: SVOM/VT optical candidate
  99. GRB 250106A: Swift ToO observations
  100. GRB 241229A: SVOM/VT optical upperlimit

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