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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"

45501 results found.

  1. EP250111a: SAO RAS optical upper limit
  2. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  3. GRB 250114B: a short GRB detected with INTEGRAL
  4. EP250108a: correction to GCN 38908
  5. GRB 250114A: Enhanced Swift-XRT position
  6. GRB 250113A: INTEGRAL/SPI-ACS detection
  7. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  8. GRB 250114A: REM detection of the optical and NIR counterpart
  9. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  10. Swift GRB250114A: Global MASTER-Net OT detection
  11. GRB 250114A: LCO optical observations
  12. GRB 250114A: TRT optical observations
  13. Swift GRB 250114A: Global MASTER-Net observations report
  14. GRB 250114A: Swift detection of a burst with an optical counterpart
  15. GRB 250101A: Terskol Zeiss-2000 optical observations
  16. EP250108a / AT 2025kg: SAO RAS optical observations
  17. EP241021a: SMA radio observation
  18. GRB 250113A: SVOM/GRM observation of a long burst
  19. GRB 250107A: VZLUSAT-2 detection
  20. EP250109b: optical upper limits with the Liverpool Telescope
  21. GRB 250109A / EP250109a: GRBAlpha detection
  22. GRB 250107D: GRBAlpha detection
  23. GRB 250106A: Swift-XRT afterglow detection
  24. Fermi trigger No 758442826: Global MASTER-Net observations report
  25. EP250111a: KAIT optical observations
  26. GRB 250109A / EP250109a: Mephisto optical upper limits
  27. EP250108a: Mephisto detection
  28. EP250111a: Mondy optical observation
  29. EP250108a / AT 2025kg: LCO optical observations
  30. EP250111a: Global MASTER-Net observations report
  31. EP250111a: Swift/XRT detection and fading
  32. EP250108a / AT 2025kg: Swift UVOT detections
  33. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  34. EP250108a: optical follow-up observations with the Liverpool Telescope
  35. EP250111a: NOT likely optical counterpart
  36. EP250111a: a new X-ray transient detected by Einstein Probe
  37. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  38. GRB 250101B: Fermi GBM Observation
  39. EP250108a: further NOT optical observations
  40. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  41. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  42. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  43. GRB 250108A: Swift/XRT afterglow fading
  44. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  45. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  46. Konus-Wind detection of GRB 250107C
  47. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  48. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  49. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  50. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  51. GRB 250101A: CMO RC-500 optical observations
  52. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  53. EP250108a: EP-FXT follow-up observation
  54. GRB 250109A: Fermi GBM Observation
  55. The EP-WXT trigger 01709130111 is likely a flaring star
  56. EP250108a: NOT optical observations
  57. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  58. GRB 250109a: GMG Optical Upper Limit
  59. EP250109a: Swift/UVOT non-detection
  60. Konus-Wind detection of GRB 250107D (short/hard)
  61. IPN triangulation of GRB 250107D (short/hard)
  62. IPN triangulation of GRB 250107C
  63. EP250108a: Liverpool Telescope likely optical counterpart
  64. GRB 250108B: Gemini-North likely redshift z = 2.197
  65. GRB 250108B: Swift-BAT refined analysis
  66. GRB 250108B: 1.3m DFOT upper limit
  67. GRB 250108B: REM optical/NIR upper limits
  68. GRB 250109A /EP250109a: Fermi GBM Final Localization
  69. EP250109a: SVOM/VT optical candidate
  70. EP250109a: Global MASTER-Net observations report
  71. GRB 250107C: SVOM/GRM observation
  72. GRB 250101A: Terskol K-800 optical observations
  73. EP250109a: GOTO optical upper limits
  74. EP250109a: Swift/XRT non-detection
  75. GRB 250108A: Swift/UVOT Upper Limits
  76. EP250108a: Global MASTER-Net observations report
  77. EP250109a: EP-WXT detection of an X-ray transient
  78. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  79. GRB 250108A: NOT optical upper limit
  80. EP250108a: EP-WXT detection of an X-ray transient
  81. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  82. GRB 250108B: Swift-XRT refined Analysis
  83. Swift GRB 250108B: Global MASTER-Net observations report
  84. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  85. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  86. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  87. GRB 250103A: 1.6m Mephisto optical observations
  88. GRB 250108A: Swift-XRT afterglow detection
  89. GRB 250108A:SVOM/VT optical candidate
  90. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  91. GRB 250108B: Swift/UVOT Upper Limits
  92. GRB 250103A: Swift-XRT afterglow detection
  93. GRB 250108B: Enhanced Swift-XRT position
  94. GRB 250108B: Swift detection of a burst
  95. GRB 250108A: Swift ToO observations
  96. GRB 250108A: SVOM detection of a soft long burst
  97. GRB 250107A: Fermi GBM Observation
  98. GRB 241228B: Fermi-LAT detection
  99. Fermi GRB 250107B: Global MASTER-Net observations report
  100. GRB 250107A: Swift ToO observations

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