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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

38258 results found.

  1. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  2. GRB 241107A: INTEGRAL IBIS localization
  3. GRB 241112A: Fermi GBM Final Real-time Localization
  4. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  5. IPN triangulation of GRB 241107A (short/hard)
  6. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  7. GRB 241025C: VZLUSAT-2 detection
  8. GRB 241025A: VZLUSAT-2 detection
  9. GRB 241018A: cubesat Avion detection
  10. Fermi trigger No 752990530: Global MASTER-Net observations report
  11. GRB 241111A: Fermi GBM Final Real-time Localization
  12. GRB 241030B: TESS detection of optical counterpart
  13. Fermi trigger No 752878030: Global MASTER-Net observations report
  14. Integral GRB241109.89: Global MASTER-Net observations report
  15. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  16. EP241107a: AbAO optical upper limit
  17. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  18. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  19. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  20. GRB 241108A: Swift-XRT observations
  21. EP241107A: MASTER optical observations of xray transient
  22. EP241107a: KAIT optical observations
  23. GRB 241108A: Swift ToO observations
  24. GRB 241030A: TESS observations
  25. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  26. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  27. GRB 241025A: radio detection with the VLA
  28. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  29. EP241107a: GSP detects optical counterpart
  30. GRB 241107A: SVOM/GRM detection of a short burst
  31. GRB 241105A: EP-FXT follow-up observations
  32. GRB 241105A: SVOM/GRM observation
  33. GRB 241105a: PRIME near-infrared upper limits
  34. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  35. EP241107a: GIT optical observations
  36. EP241107a: Global MASTER-Net observations report
  37. EP241107a: SVOM/C-GFT optical observations
  38. GRB 241025A: LBT optical observations
  39. GRB241105A: Gemini-South Optical Afterglow Detection
  40. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  41. GRB 241105A: Swift/UVOT Detection
  42. EP241101a: CrAO ZTSH optical observations
  43. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  44. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  45. GRB 241105A: BOOTES-7 optical detection
  46. GRB 241030A: Mondy optical observations
  47. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  48. Konus-Wind detection of GRB 241105A (short with extended emission)
  49. Konus-Wind detection of GRB 241021A
  50. GRB 241105A: SVOM/VT optical afterglow observations
  51. GRB 241105A: Swift-XRT afterglow detection
  52. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  53. GRB 241104A: Swift-XRT observations
  54. GRB 240511A: LCO upper limits
  55. GRB 241104A: Fermi GBM Observation
  56. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  57. GRB 241105A: Swift ToO observations
  58. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  59. GRB 241104A: Swift ToO observations
  60. GRB 241104A: NOT optical non-detection
  61. GRB 241105A: GOTO tentative optical counterpart candidate
  62. Fermi GRB 241105A: Global MASTER-Net observations report
  63. GRB 241104A: SVOM/VT optical candidate
  64. GRB 241105A: Fermi GBM Final Real-time Localization
  65. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  66. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  67. GRB 241104A: SVOM/GRM observation
  68. EP241104a: EP detection of GRB 241104A X-ray emission
  69. GRB 241010A: host galaxy redshift z = 0.977
  70. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  71. GRB 240821A: further radio observations with the VLA
  72. Fermi GRB 241104A: Global MASTER-Net observations report
  73. GRB 241104A: Fermi GBM Final Real-time Localization
  74. GRB 241030A: GRBAlpha detection
  75. EP241103a: GIT optical upper limit
  76. Fermi trigger No 752365806: Global MASTER-Net observations report
  77. EP241101a: Optical upper limits with Kinder observations
  78. EP241101a: OHP/T193 optical observations
  79. EP241103a: EP observation update
  80. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  81. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  82. EP241103a: GSP optical upper limit
  83. EP241103A: LCO optical observations
  84. EP241103a: Global MASTER-Net observations report
  85. GRB 241030A: Rapid release of TESS data.
  86. EP241101a: Global MASTER-Net observations report
  87. GRB 241029A: GRBAlpha detection
  88. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  89. Swift GRB 241101A: Global MASTER-Net observations report
  90. GRB 241101A: FRAM-ORM optical limit
  91. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  92. EP241021a: Upper limit from Konus-Wind observations
  93. GRB 241101A: Swift-BAT refined analysis
  94. GRB 241030A: further SAO RAS optical observations
  95. GRB 241030A: Optical Observations via Virtual Telescope Project
  96. GRB 241030B: Swift-XRT refined Analysis
  97. GRB 241026A: SAO RAS optical observations
  98. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  99. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  100. GRB 241101A: Swift detection of a burst

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