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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"

11528 results found.

  1. GRB 241115C: Fermi GBM Observation
  2. GRB 241115A: Fermi GBM Observation
  3. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  4. Fermi GRB 241115B: Global MASTER-Net observations report
  5. GRB 241115B: Fermi GBM Final Real-time Localization
  6. EP241113a: No Detection in Fermi-GBM Observations
  7. Fermi GRB 241115A: Global MASTER-Net observations report
  8. GRB 241115A: Fermi GBM Final Real-time Localization
  9. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  10. Fermi GRB 241114A: Global MASTER-Net observations report
  11. GRB 241114A: Fermi GBM Final Real-time Localization
  12. Fermi-LAT gamma-ray observations of IceCube-241113A
  13. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  14. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  15. Fermi trigger No 753166198: Global MASTER-Net observations report
  16. GRB 241105A: ATCA Radio Upper Limits
  17. Fermi GRB 241112A: Global MASTER-Net observations report
  18. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  19. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  20. GRB 241107A: INTEGRAL IBIS localization
  21. GRB 241112A: Fermi GBM Final Real-time Localization
  22. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  23. IPN triangulation of GRB 241107A (short/hard)
  24. GRB 241025C: VZLUSAT-2 detection
  25. GRB 241025A: VZLUSAT-2 detection
  26. Fermi trigger No 752990530: Global MASTER-Net observations report
  27. GRB 241111A: Fermi GBM Final Real-time Localization
  28. GRB 241030B: TESS detection of optical counterpart
  29. Fermi trigger No 752878030: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  31. GRB 241030A: TESS observations
  32. GRB 241025A: radio detection with the VLA
  33. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  34. GRB 241105A: EP-FXT follow-up observations
  35. GRB 241105A: SVOM/GRM observation
  36. GRB 241105a: PRIME near-infrared upper limits
  37. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  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. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  43. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  44. GRB 241105A: BOOTES-7 optical detection
  45. GRB 241030A: Mondy optical observations
  46. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  47. Konus-Wind detection of GRB 241105A (short with extended emission)
  48. GRB 241105A: SVOM/VT optical afterglow observations
  49. GRB 241105A: Swift-XRT afterglow detection
  50. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  51. GRB 241104A: Swift-XRT observations
  52. GRB 240511A: LCO upper limits
  53. GRB 241104A: Fermi GBM Observation
  54. GRB 241105A: Swift ToO observations
  55. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  56. GRB 241104A: Swift ToO observations
  57. GRB 241104A: NOT optical non-detection
  58. GRB 241105A: GOTO tentative optical counterpart candidate
  59. Fermi GRB 241105A: Global MASTER-Net observations report
  60. GRB 241104A: SVOM/VT optical candidate
  61. GRB 241105A: Fermi GBM Final Real-time Localization
  62. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  63. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  64. GRB 241104A: SVOM/GRM observation
  65. EP241104a: EP detection of GRB 241104A X-ray emission
  66. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  67. GRB 240821A: further radio observations with the VLA
  68. Fermi GRB 241104A: Global MASTER-Net observations report
  69. GRB 241104A: Fermi GBM Final Real-time Localization
  70. GRB 241030A: GRBAlpha detection
  71. Fermi trigger No 752365806: Global MASTER-Net observations report
  72. GRB 241030A: Rapid release of TESS data.
  73. GRB 241029A: GRBAlpha detection
  74. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  75. GRB241030A: OHP/T193 optical observations
  76. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  77. GRB 241026A: SAO RAS optical observations
  78. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  79. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  80. GRB 241030B: Montarrenti Observatory optical upper limit
  81. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  82. Fermi trigger No 752083996: Global MASTER-Net observations report
  83. GRB 241030A: Fermi GBM Observation
  84. GRB 241030B : GIT optical upper limits
  85. GRB 241030B: LCOGT Optical Upper Limits
  86. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  87. Fermi trigger No 752006065: Global MASTER-Net observations report
  88. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  89. GRB 241030B: SVOM/GRM observation
  90. GRB 241030B : MITSuME Akeno optical upper limits
  91. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  92. GRB 241030B: SVOM/VT optical afterglow observations
  93. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  94. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  95. GRB241030B: Fermi GBM Observation
  96. GRB 241030B: BTA observations
  97. GRB 241029A: SVOM/VT optical afterglow observations
  98. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  99. GRB 241030B: optical observations from the INAF Asiago Observatory
  100. GRB 241030B: SAO RAS optical observations

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