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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"

45720 results found.

  1. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  2. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  3. GRB 250114B: Swift-XRT observations
  4. GRB 250114A: LCO optical counterpart detection.
  5. GRB 250114B: OHP/T193 optical upper limit
  6. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  7. GRB 250114A: Swift-XRT refined Analysis
  8. Integral GRB250114.55: Global MASTER-Net observations report
  9. GRB 250114A: LCOGT optical afterglow i-band detection
  10. GRB 250114B : GIT optical upper limit
  11. GRB 250114B: Swift ToO observations
  12. EP250111a: SAO RAS optical upper limit
  13. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  14. GRB 250114B: a short GRB detected with INTEGRAL
  15. EP250108a: correction to GCN 38908
  16. GRB 250114A: Enhanced Swift-XRT position
  17. GRB 250113A: INTEGRAL/SPI-ACS detection
  18. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  19. GRB 250114A: REM detection of the optical and NIR counterpart
  20. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  21. Swift GRB250114A: Global MASTER-Net OT detection
  22. GRB 250114A: LCO optical observations
  23. GRB 250114A: TRT optical observations
  24. Swift GRB 250114A: Global MASTER-Net observations report
  25. GRB 250114A: Swift detection of a burst with an optical counterpart
  26. GRB 250101A: Terskol Zeiss-2000 optical observations
  27. EP250108a / AT 2025kg: SAO RAS optical observations
  28. EP241021a: SMA radio observation
  29. GRB 250113A: SVOM/GRM observation of a long burst
  30. GRB 250107A: VZLUSAT-2 detection
  31. EP250109b: optical upper limits with the Liverpool Telescope
  32. GRB 250109A / EP250109a: GRBAlpha detection
  33. GRB 250107D: GRBAlpha detection
  34. GRB 250106A: Swift-XRT afterglow detection
  35. Fermi trigger No 758442826: Global MASTER-Net observations report
  36. EP250111a: KAIT optical observations
  37. GRB 250109A / EP250109a: Mephisto optical upper limits
  38. EP250108a: Mephisto detection
  39. EP250111a: Mondy optical observation
  40. EP250108a / AT 2025kg: LCO optical observations
  41. EP250111a: Global MASTER-Net observations report
  42. EP250111a: Swift/XRT detection and fading
  43. EP250108a / AT 2025kg: Swift UVOT detections
  44. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  45. EP250108a: optical follow-up observations with the Liverpool Telescope
  46. EP250111a: NOT likely optical counterpart
  47. EP250111a: a new X-ray transient detected by Einstein Probe
  48. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  49. GRB 250101B: Fermi GBM Observation
  50. EP250108a: further NOT optical observations
  51. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  52. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  53. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  54. GRB 250108A: Swift/XRT afterglow fading
  55. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  56. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  57. Konus-Wind detection of GRB 250107C
  58. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  59. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  60. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  61. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  62. GRB 250101A: CMO RC-500 optical observations
  63. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  64. EP250108a: EP-FXT follow-up observation
  65. GRB 250109A: Fermi GBM Observation
  66. The EP-WXT trigger 01709130111 is likely a flaring star
  67. EP250108a: NOT optical observations
  68. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  69. GRB 250109a: GMG Optical Upper Limit
  70. EP250109a: Swift/UVOT non-detection
  71. Konus-Wind detection of GRB 250107D (short/hard)
  72. IPN triangulation of GRB 250107D (short/hard)
  73. IPN triangulation of GRB 250107C
  74. EP250108a: Liverpool Telescope likely optical counterpart
  75. GRB 250108B: Gemini-North likely redshift z = 2.197
  76. GRB 250108B: Swift-BAT refined analysis
  77. GRB 250108B: 1.3m DFOT upper limit
  78. GRB 250108B: REM optical/NIR upper limits
  79. GRB 250109A /EP250109a: Fermi GBM Final Localization
  80. EP250109a: SVOM/VT optical candidate
  81. EP250109a: Global MASTER-Net observations report
  82. GRB 250107C: SVOM/GRM observation
  83. GRB 250101A: Terskol K-800 optical observations
  84. EP250109a: GOTO optical upper limits
  85. EP250109a: Swift/XRT non-detection
  86. GRB 250108A: Swift/UVOT Upper Limits
  87. EP250108a: Global MASTER-Net observations report
  88. EP250109a: EP-WXT detection of an X-ray transient
  89. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  90. GRB 250108A: NOT optical upper limit
  91. EP250108a: EP-WXT detection of an X-ray transient
  92. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  93. GRB 250108B: Swift-XRT refined Analysis
  94. Swift GRB 250108B: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  96. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  97. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  98. GRB 250103A: 1.6m Mephisto optical observations
  99. GRB 250108A: Swift-XRT afterglow detection
  100. GRB 250108A:SVOM/VT optical candidate

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