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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"

34091 results found.

  1. GRB 221023A: Fermi GBM Final Localization
  2. GRB 221023A: AGILE detection of a burst
  3. GRB 221022A: Swift/BAT-GUANO detection
  4. GRB 221022B: Swift/BAT-GUANO detection outside the coded FOV
  5. GRB 221022B: AGILE detection
  6. GRB 221009A: James Webb Space Telescope Observations
  7. GRB 221022B: Fermi GBM Final Real-time Localization
  8. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  9. GRB 221009A: optical observations, SN photometric evidence
  10. GRB 221021A: Swift/BAT-GUANO detection outside the coded FOV
  11. GRB 221022A: Fermi GBM Final Real-time Localization
  12. GRB 221020A: Detection by GRBAlpha
  13. SGR 1935+21542: VZLUSAT-2 and GRBAlpha joint detection
  14. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  15. GRB 221021A: Fermi GBM Final Real-time Localization
  16. GRB 221009A: 1.3m DFOT Optical Observations
  17. Fermi GBM trigger 687320613 / 221013100 (GRB 221013B) is not a GRB
  18. GRB221009A: LBT optical imaging
  19. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  20. GRB 221017A: Swift-XRT observations
  21. GRB 221020A: Fermi GBM Final Real-time Localization
  22. Improved IPN localization for GRB 221009A (BepiColombo-MGNS light curve)
  23. GRB 221009A: TNG NIR detection
  24. GRB 221009A: BOAO NIR detections
  25. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  26. GRB 221009A: Spectroscopic detection of emerging SN features
  27. GRB 221009A: Continued LDT Afterglow Monitoring
  28. GRB 221013B: Swift/BAT-GUANO detection
  29. SGR 1935+2154: Bursting activity detected by VZLUSAT-2
  30. GRB 221009A: GRANDMA observations
  31. The probability of observing GRB 221009A at z = 0.151
  32. GRB 221009A: Medicina Radio Telescope observations
  33. GRB 221017A: Swift ToO observations
  34. GRB 221009A: Second epoch of NuSTAR data
  35. IPN triangulation of GRB 221017A (long)
  36. GRB 221016A: Swift-BAT refined analysis
  37. GRB 221016A: Swift/UVOT Detection
  38. GRB 221016A: Swift-XRT refined Analysis
  39. Konus-Wind detection of GRB 221016A
  40. GRB 221016A: Fermi GBM observation
  41. GRB 220926B: Detection by GRBAlpha
  42. GRB 221009A: A type I BdHN of exceptional energetics
  43. GRB 221016A: z-band upper limit, possible afterglow brightening
  44. GRB 221017A: MAXI/GSC detection
  45. GRB 221016A: Enhanced Swift-XRT position
  46. GRB 221016A: LCOGT Optical Afterglow Detection
  47. GRB 221016A: Swift detection of a burst
  48. GRB 221016A: Fermi GBM Final Real-time Localization
  49. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  50. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  51. GRB 221009A: LEIA X-ray Afterglow Detection
  52. GRB 221009A: ATCA radio spectrum
  53. GRB 221009A: VLT spectroscopic detection of the host galaxy
  54. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  55. GRB 221009A: ATCA detection
  56. GRB 221009A: Armchair Energetics
  57. GRB 221009A: ALMA and ACA detections
  58. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  59. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  60. GRB 221009A: Pan-STARRS optical photometry
  61. GRB 221009A: VLA detection
  62. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  63. GRB 221009A: continued REM optical/NIR observations and evidence for an achromatic steepening in the afterglow light curve
  64. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  65. GRB 221009A: OHP optical observations
  66. GRB221009A: RTT-150 optical observations
  67. GRB 221009A: HEBS detection
  68. GRB 221009A: Gemini-South Infrared Afterglow Detection
  69. GRB221009A: Gemini-South Optical Afterglow Detection
  70. GRB 221009A: a 397.7 GeV photon observed by Fermi-LAT at 0.4 day after the GBM trigger
  71. GRB 221014A: Fermi GBM Final Real-time Localization
  72. GRB 221009A: Gamma-ray Detection by SIRI-2
  73. MAXI GRB 221006A: Redshifts of the possible host galaxies
  74. GRB 221009A: search for neutrinos with KM3NeT
  75. GRB 221009A: MeerKAT detection
  76. GRB 221009A: Lowell Discovery Telescope Afterglow Detection
  77. GRB221009A: LCOGT Continued Observations - Optical Upper Limits
  78. Fermi Gamma-ray Burst Monitor continues to detect SGR 1935+2154
  79. GRB 221009A/Swift J1913.1+1946: low-frequency ASKAP observations
  80. GRB 221006A: Swift-XRT afterglow detection
  81. GRB 221009A: MITSuME Okayama optical observation
  82. GRB 221009A: Sayan observatory 1.6-m telescope observations
  83. GRB 221009A: GMG observation
  84. GRB 221013B: Fermi GBM Final Real-time Localization
  85. GRB 221013A: Fermi GBM Final Real-time Localization
  86. Afterglow limits of GRB 221006A from OHP
  87. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  88. GRB 221009A/Swift J1913.1+1946: SMA observations
  89. GRB 221009A: COATLI Continued Monitoring of the Afterglow
  90. GRB 221009A/Swift J1913.1+1946: eMERLIN observations
  91. GRB 220829A: Detection by GRBAlpha
  92. GRB 220826B: Detection by GRBAlpha
  93. GRB 221009A: NuSTAR Detection
  94. GRB 221009A: NICER follow-up observations
  95. GRB 221009A: LCOGT Optical Afterglow Detection
  96. GRB 221009A: COATLI Detection of the Afterglow
  97. GRB 221009A: planned observation with the Imaging X-ray Polarimetry Explorer (IXPE)
  98. GRB 221009A (Swift J1913.1+1946): Swift-BAT refined analysis
  99. Fermi Gamma-ray Burst Monitor trigger 221011452/687178284 is not a GRB
  100. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation

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