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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"

35948 results found.

  1. GRB 221017A: MAXI/GSC detection
  2. GRB 221016A: Enhanced Swift-XRT position
  3. GRB 221016A: LCOGT Optical Afterglow Detection
  4. GRB 221016A: Swift detection of a burst
  5. GRB 221016A: Fermi GBM Final Real-time Localization
  6. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  7. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  8. GRB 221009A: LEIA X-ray Afterglow Detection
  9. GRB 221009A: ATCA radio spectrum
  10. GRB 221009A: VLT spectroscopic detection of the host galaxy
  11. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  12. GRB 221009A: ATCA detection
  13. GRB 221009A: Armchair Energetics
  14. GRB 221009A: ALMA and ACA detections
  15. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  16. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  17. GRB 221009A: Pan-STARRS optical photometry
  18. GRB 221009A: VLA detection
  19. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  20. GRB 221009A: continued REM optical/NIR observations and evidence for an achromatic steepening in the afterglow light curve
  21. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  22. GRB 221009A: OHP optical observations
  23. GRB221009A: RTT-150 optical observations
  24. GRB 221009A: HEBS detection
  25. GRB 221009A: Gemini-South Infrared Afterglow Detection
  26. GRB221009A: Gemini-South Optical Afterglow Detection
  27. GRB 221009A: a 397.7 GeV photon observed by Fermi-LAT at 0.4 day after the GBM trigger
  28. GRB 221014A: Fermi GBM Final Real-time Localization
  29. GRB 221009A: Gamma-ray Detection by SIRI-2
  30. MAXI GRB 221006A: Redshifts of the possible host galaxies
  31. GRB 221009A: search for neutrinos with KM3NeT
  32. GRB 221009A: MeerKAT detection
  33. GRB 221009A: Lowell Discovery Telescope Afterglow Detection
  34. GRB221009A: LCOGT Continued Observations - Optical Upper Limits
  35. Fermi Gamma-ray Burst Monitor continues to detect SGR 1935+2154
  36. GRB 221009A/Swift J1913.1+1946: low-frequency ASKAP observations
  37. GRB 221006A: Swift-XRT afterglow detection
  38. GRB 221009A: MITSuME Okayama optical observation
  39. GRB 221009A: Sayan observatory 1.6-m telescope observations
  40. GRB 221009A: GMG observation
  41. GRB 221013B: Fermi GBM Final Real-time Localization
  42. GRB 221013A: Fermi GBM Final Real-time Localization
  43. Afterglow limits of GRB 221006A from OHP
  44. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  45. GRB 221009A/Swift J1913.1+1946: SMA observations
  46. GRB 221009A: COATLI Continued Monitoring of the Afterglow
  47. GRB 221009A/Swift J1913.1+1946: eMERLIN observations
  48. GRB 220829A: Detection by GRBAlpha
  49. GRB 220826B: Detection by GRBAlpha
  50. GRB 221009A: NuSTAR Detection
  51. GRB 221009A: NICER follow-up observations
  52. GRB 221009A: LCOGT Optical Afterglow Detection
  53. GRB 221009A: COATLI Detection of the Afterglow
  54. GRB 221009A: planned observation with the Imaging X-ray Polarimetry Explorer (IXPE)
  55. GRB 221009A (Swift J1913.1+1946): Swift-BAT refined analysis
  56. Fermi Gamma-ray Burst Monitor trigger 221011452/687178284 is not a GRB
  57. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
  58. GRB 221009A: Detection by GRBAlpha
  59. GRB 221009A: Sintez-Newton/CrAO optical observations
  60. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  61. GRB 221006A: Swift ToO observations
  62. GRB 221011A: Fermi GBM Final Real-time Localization
  63. Swift/XRT discovery of multiple dust-scattering X-ray rings around GRB 221009A
  64. GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
  65. GRB 221009A: BlackGEM optical observations
  66. LHAASO observed GRB 221009A with more than 5000 VHE photons up to around 18 TeV
  67. GRB 221009A: NOEMA mm detection
  68. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  69. GRB 221009A: Continued Swift/XRT observations
  70. GRB 221009A/Swift J1913.1+1946: Assy optical afterglow observation
  71. GRB 221009A/Swift J1913.1+1946: Lick/Nickel telescope optical observations
  72. Konus-Wind detection of GRB 221009A
  73. GRB 221009A: Lulin SLT-40cm optical observations
  74. Swift J1913.1+1946: New Photometry
  75. GRB 221009A: Upper limits from a neutrino search with IceCube
  76. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  77. GRB221009A/Swift J1913.1+1946: SRG/ART-XC observation
  78. GRB 221009A / Swift J1913.1+1946: GIT detection of the optical afterglow
  79. GRB221009A/Swift J1913.1+1946: Solar Orbiter STIX measurements
  80. GRB221009A/Swift J1913.1+1946: INTEGRAL SPI/ACS observations
  81. ​GRB 221009A: Multi-color detection of the optical
  82. GRB 221009A: Fermi-LAT refined analysis
  83. GRB 221009A (Swift J1913.1+1946): AGILE/GRID detection
  84. GRB 221009: Swift/UVOT Detection
  85. GRB 221009A or Swift J1913.1+1946: PRIME near-infrared detection
  86. GRB 221009A/Swift J1913.1+1946: AMI-LA observations
  87. GRB 221009A: REM optical and NIR detection of the afterglow
  88. GRB 221009A: Swift-XRT refined Analysis
  89. GRB 221009A (Swift J1913.1+1946): AGILE/MCAL detection
  90. GRB 221009A: Redshift from X-shooter/VLT
  91. GRB 221009A: Nanshan/NEXT photometry and Xinglong-2.16m spectroscopy
  92. GRB 221009A (Swift J1913.1+1946): MeerLICHT observations
  93. GRB 221009A (Swift J1913.1+1946): Mondy optical observations
  94. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  95. GRB 221009A: Fermi GBM observation
  96. IPN triangulation of extremely bright GRB 221009A
  97. Swift J1913.1+1946: Optical photometry
  98. Swift J1913.1+1946: Liverpool Telescope imaging and spectroscopy
  99. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  100. GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB

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