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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"

46043 results found.

  1. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  2. Swift Trigger 1282245 is not a GRB
  3. GRB 250116A: Fermi-LAT detection
  4. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  5. GRB 250114B: Swift-XRT afterglow detection
  6. GRB 250114B: SVOM/VT upper limit
  7. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  8. EP250108a: MeerKAT radio upper limit
  9. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  10. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  11. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  12. Konus-Wind detection of GRB 250113A
  13. IPN triangulation of GRB 250113A
  14. GRB 250114B: Liverpool Telescope optical upper limit
  15. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  16. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  17. GRB 250114B: Swift-XRT observations
  18. GRB 250114A: LCO optical counterpart detection.
  19. GRB 250114B: OHP/T193 optical upper limit
  20. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  21. GRB 250114A: Swift-XRT refined Analysis
  22. Integral GRB250114.55: Global MASTER-Net observations report
  23. GRB 250114A: LCOGT optical afterglow i-band detection
  24. GRB 250114B : GIT optical upper limit
  25. GRB 250114B: Swift ToO observations
  26. EP250111a: SAO RAS optical upper limit
  27. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  28. GRB 250114B: a short GRB detected with INTEGRAL
  29. EP250108a: correction to GCN 38908
  30. GRB 250114A: Enhanced Swift-XRT position
  31. GRB 250113A: INTEGRAL/SPI-ACS detection
  32. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  33. GRB 250114A: REM detection of the optical and NIR counterpart
  34. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  35. Swift GRB250114A: Global MASTER-Net OT detection
  36. GRB 250114A: LCO optical observations
  37. GRB 250114A: TRT optical observations
  38. Swift GRB 250114A: Global MASTER-Net observations report
  39. GRB 250114A: Swift detection of a burst with an optical counterpart
  40. GRB 250101A: Terskol Zeiss-2000 optical observations
  41. EP250108a / AT 2025kg: SAO RAS optical observations
  42. EP241021a: SMA radio observation
  43. GRB 250113A: SVOM/GRM observation of a long burst
  44. GRB 250107A: VZLUSAT-2 detection
  45. EP250109b: optical upper limits with the Liverpool Telescope
  46. GRB 250109A / EP250109a: GRBAlpha detection
  47. GRB 250107D: GRBAlpha detection
  48. GRB 250106A: Swift-XRT afterglow detection
  49. Fermi trigger No 758442826: Global MASTER-Net observations report
  50. EP250111a: KAIT optical observations
  51. GRB 250109A / EP250109a: Mephisto optical upper limits
  52. EP250108a: Mephisto detection
  53. EP250111a: Mondy optical observation
  54. EP250108a / AT 2025kg: LCO optical observations
  55. EP250111a: Global MASTER-Net observations report
  56. EP250111a: Swift/XRT detection and fading
  57. EP250108a / AT 2025kg: Swift UVOT detections
  58. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  59. EP250108a: optical follow-up observations with the Liverpool Telescope
  60. EP250111a: NOT likely optical counterpart
  61. EP250111a: a new X-ray transient detected by Einstein Probe
  62. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  63. GRB 250101B: Fermi GBM Observation
  64. EP250108a: further NOT optical observations
  65. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  66. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  67. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  68. GRB 250108A: Swift/XRT afterglow fading
  69. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  70. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  71. Konus-Wind detection of GRB 250107C
  72. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  73. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  74. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  75. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  76. GRB 250101A: CMO RC-500 optical observations
  77. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  78. EP250108a: EP-FXT follow-up observation
  79. GRB 250109A: Fermi GBM Observation
  80. The EP-WXT trigger 01709130111 is likely a flaring star
  81. EP250108a: NOT optical observations
  82. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  83. GRB 250109a: GMG Optical Upper Limit
  84. EP250109a: Swift/UVOT non-detection
  85. Konus-Wind detection of GRB 250107D (short/hard)
  86. IPN triangulation of GRB 250107D (short/hard)
  87. IPN triangulation of GRB 250107C
  88. EP250108a: Liverpool Telescope likely optical counterpart
  89. GRB 250108B: Gemini-North likely redshift z = 2.197
  90. GRB 250108B: Swift-BAT refined analysis
  91. GRB 250108B: 1.3m DFOT upper limit
  92. GRB 250108B: REM optical/NIR upper limits
  93. GRB 250109A /EP250109a: Fermi GBM Final Localization
  94. EP250109a: SVOM/VT optical candidate
  95. EP250109a: Global MASTER-Net observations report
  96. GRB 250107C: SVOM/GRM observation
  97. GRB 250101A: Terskol K-800 optical observations
  98. EP250109a: GOTO optical upper limits
  99. EP250109a: Swift/XRT non-detection
  100. GRB 250108A: Swift/UVOT Upper Limits

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