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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"

45716 results found.

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

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