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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"

28059 results found.

  1. GRB 221016A: Fermi GBM observation
  2. GRB 221009A: A type I BdHN of exceptional energetics
  3. MAXI GRB221017.24: Global MASTER-Net observations report
  4. GRB 221016A: z-band upper limit, possible afterglow brightening
  5. GRB 221017A: MAXI/GSC detection
  6. GRB 221016A: Enhanced Swift-XRT position
  7. GRB 221016A: LCOGT Optical Afterglow Detection
  8. GRB 221016A: Swift detection of a burst
  9. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  10. Konus-Wind observation of the recent SGR 1935+2154 activity
  11. GRB 221009A: VLT spectroscopic detection of the host galaxy
  12. GRB 221009A: Armchair Energetics
  13. GRB 221009A: ALMA and ACA detections
  14. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  15. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  16. GRB 221009A: continued REM optical/NIR observations and evidence for an achromatic steepening in the afterglow light curve
  17. GRB 221009A: OHP optical observations
  18. MAXI GRB 221006A: Redshifts of the possible host galaxies
  19. GRB221009A: LCOGT Continued Observations - Optical Upper Limits
  20. GRB 221009A/Swift J1913.1+1946: low-frequency ASKAP observations
  21. GRB 221006A: Swift-XRT afterglow detection
  22. GRB 221009A: MITSuME Okayama optical observation
  23. GRB 221009A: Sayan observatory 1.6-m telescope observations
  24. GRB 221009A: GMG observation
  25. Afterglow limits of GRB 221006A from OHP
  26. GRB221009A: optical afterglow measurements from Konkoly Observatory
  27. GRB 221009A/Swift J1913.1+1946: SMA observations
  28. INTEGRAL shows increasing activity in SGR J1935+2154
  29. GRB 221009A: COATLI Continued Monitoring of the Afterglow
  30. INTEGRAL detection of a burst from SGR J1935+2154
  31. GRB 221009A: NICER follow-up observations
  32. GRB 221009A: LCOGT Optical Afterglow Detection
  33. GRB 221009A: COATLI Detection of the Afterglow
  34. GRB 221009A (Swift J1913.1+1946): Swift-BAT refined analysis
  35. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  36. Swift/XRT discovery of multiple dust-scattering X-ray rings around GRB 221009A
  37. GRB 221009A: BlackGEM optical observations
  38. GRB 221009A/Swift J1913.1+1946: Lick/Nickel telescope optical observations
  39. Konus-Wind detection of GRB 221009A
  40. GRB 221009A: Lulin SLT-40cm optical observations
  41. GRB 221009A: Upper limits from a neutrino search with IceCube
  42. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  43. GRB221009A/Swift J1913.1+1946: SRG/ART-XC observation
  44. GRB 221009A / Swift J1913.1+1946: GIT detection of the optical afterglow
  45. GRB221009A/Swift J1913.1+1946: Solar Orbiter STIX measurements
  46. GRB221009A/Swift J1913.1+1946: INTEGRAL SPI/ACS observations
  47. ​GRB 221009A: Multi-color detection of the optical
  48. GRB 221009A: Fermi-LAT refined analysis
  49. GRB 221009: Swift/UVOT Detection
  50. GRB221009A/Swift J1913.1+1946: ATA follow-up observations
  51. GRB 221009A or Swift J1913.1+1946: PRIME near-infrared detection
  52. GRB 221009A/Swift J1913.1+1946: AMI-LA observations
  53. GRB 221009A: REM optical and NIR detection of the afterglow
  54. GRB 221009A: Swift-XRT refined Analysis
  55. GRB 221009A: Nanshan/NEXT photometry and Xinglong-2.16m spectroscopy
  56. GRB 221009A (Swift J1913.1+1946): MeerLICHT observations
  57. Swift J1913.1+1946 : Pre-discovery limits from ZTF
  58. Swift J1913.1+1946: Optical photometry
  59. Fermi trigger No 687014224: Global MASTER-Net observations report
  60. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  61. GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB
  62. Swift GRB221009.59: Global MASTER-Net OT detection
  63. GRB 221008A: Swift-XRT observations
  64. Swift J1913.1+1946 a new bright hard X-ray and optical transient
  65. GRB 221008A: MAXI/GSC detection
  66. GRB 221006A: Swift-XRT observations
  67. GRB 221006A: MAXI/GSC detection
  68. GRB 220930A: MITSuME Akeno optical upper limits
  69. GRB 220912A: Detection by VZLUSAT-2
  70. Fermi trigger No 686588176: Global MASTER-Net observations report
  71. Fermi GBM trigger 686350260/221001869 is not a GRB
  72. GRB 220930A: AbAO Optical Upper Limit
  73. GRB 220930A: Swift-BAT refined analysis
  74. GRB 220930A: Swift-XRT refined Analysis
  75. GRB 220930A: LCOGT Optical Upper Limits
  76. GRB 220930A: Swift/UVOT Upper Limits
  77. GRB 220930A: Enhanced Swift-XRT position
  78. GRB 220930A: COATLI Upper Limits
  79. GRB 220930A: Swift detection of a burst
  80. Fermi-LAT gamma-ray observations of IceCube-220928A
  81. IceCube-220928A: Upper limits from a search for additional neutrino events in IceCube
  82. IPN triangulation of GRB 220927A (long)
  83. GRB 220921A: LCOGT Optical Observations
  84. GRB 220927A: Fermi GBM Final Localization
  85. GRB 220924A: Fermi GBM detection
  86. Ultra-long GRB 220525B: Konus-Wind and Fermi-GBM detection
  87. Swift Trigger 1125354 (GRB 220926A) is not a GRB
  88. Analysis of long GRB 220926B detected by INTEGRAL
  89. GRB 220926A: Swift detection of a burst
  90. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  91. GRB 220921A: further MeerLICHT observations
  92. GRB 220921A: DDOTI Detection of the Afterglow
  93. GRB 220921A: Fermi GBM detection
  94. GRB 220921A: MeerLICHT afterglow observations
  95. GRB 220921A: Swift-XRT Observations
  96. GRB 220921A: Fermi-LAT detection
  97. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  98. IceCube-220918A: Upper limits from a search for additional neutrino events in IceCube
  99. Fermi trigger No 684894705: Global MASTER-Net observations report
  100. IceCube-220907A: No significant detection in HAWC

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