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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"
  1. GRB 171108A: Fermi GBM detection
  2. GRB 171102A CALET Gamma-Ray Burst Monitor detection
  3. GRB 171101A CALET Gamma-Ray Burst Monitor detection
  4. INTEGRAL observation of IceCube-171106A
  5. GRB 171030A: MASTER OT J034412.48-263556.5 featureless continuum spectrum from Lijiang 2.4m (China) telescope and 2m the Himalayan Chandra
  6. GRB 171010A: possible SN component
  7. Fermi-GBM Trigger 531686417 / 171106778 is not related to ICECUBE-171106A
  8. IceCube-171106A - IceCube observation of a high-energy neutrino candidate
  9. AMON ICECUBE EHE 130214 (close by time to Fermi trigger): MASTER early follow-up observations
  10. GRB 171103A: AstroSat CZTI detection
  11. GRB 171030A: MASTER inspection of the IPN error box of the short GRB.
  12. Konus-Wind observation of GRB 171103A (short/hard)
  13. GRB 171103A: Fermi GBM observation
  14. GRB 171103A: Swift-BAT refined analysis of a short GRB
  15. LIGO/Virgo G298936: NOT spectroscopy of GWFUNC-17ure
  16. Fermi GBM detections of Swift J0243.6+6124 and modification of the GBM trigger configuration
  17. GRB 171010A: VLT spectroscopic identification of the associated SN 2017htp
  18. GRB 171103A: Swift detection of a short hard burst
  19. Konus-Wind observation of GRB 171102A
  20. GRB 171102B: AbAO optical upper limit
  21. GRB 171102B: TShAO optical upper limit
  22. IPN Triangulation of GRB 171102A
  23. GRB 171102B: Nanshan 0.36m and 0.60m optical upper limits
  24. GRB 171102B: RATIR Optical and NIR Observations
  25. GRB 171102B: Swift-BAT refined analysis
  26. GRB 171102B: MITSuME Akeno optical upper limits
  27. GRB 171102B: Swift/UVOT Upper Limits
  28. GRB 171102B: Swift-XRT refined Analysis
  29. GRB 171102B: Enhanced Swift-XRT position
  30. GRB 171102A: Fermi GBM detection
  31. GRB 171102B: Swift detection of a burst
  32. GRB 171102A: Fermi-LAT detection
  33. GRB 171030A: IPN error box through NSs probability merging rate map
  34. GRB 171030A: Fermi GBM detection
  35. GRB 171030A: Swift non-localization with BAT, XRT and UVOT
  36. GRB 171030A: Swift ToO observations
  37. IPN Triangulation of GRB 171030A (short)
  38. Fermi-GBM triggers due to Swift J0243.6+6124
  39. Swift Trigger 783893: KAIT Optical Observations
  40. GRB 171027A: KAIT Optical Upper Limit
  41. Swift Triggers 784159 and 784160 are not bursts
  42. GRB 171022A: Fermi-LAT detection retraction
  43. Konus-Wind observation of GRB 171027A
  44. AMI-LA observations of the new Be X-ray binary Swift J0243.6+6124
  45. Swift Trigger 783893: LCO 1-m telescope observations
  46. Swift Trigger 783893 is probably not a GRB
  47. GRB 171027A, Swift-BAT refined analysis
  48. Retraction of high energy neutrino candidate IceCube-171028
  49. GRB 171027A: Swift/UVOT Upper Limits
  50. GRB 171027A: Swift-XRT refined Analysis
  51. GRB 171027A: Enhanced Swift-XRT position
  52. GRB 171027A: RATIR Confirmation of Fading and Photo-z
  53. GRB 171027A: VLT optical upper limits
  54. GRB 171027A: LCO 1-m telescope observations
  55. GROND observations of GRB 171027A: correction
  56. GRB 171027A: RATIR Detection of a NIR Afterglow Candidate
  57. GROND observations of GRB 171027A
  58. GRB 171027A: MASTER-OAFA (Argentina) early prompt optical observations
  59. GRB 171027A: Prompt enhanced Swift-XRT position
  60. GRB 171027A: Swift detection of a burst
  61. Konus-Wind observation of GRB 171022A
  62. IPN Triangulation of GRB 171022A
  63. GRB 171013B CALET Gamma-Ray Burst Monitor detection
  64. Fermi GBM trigger 530617076/171025401 is not a GRB
  65. Swift trigger 781740: Further analysis from Swift and Fermi/GBM
  66. Numerous Fermi-GBM Subthreshold Notices are due to Swift J0243.6+6
  67. GRB 171022A: Fermi GBM detection
  68. GRB 171022A: Fermi-LAT detection
  69. Swift Trigger 781740 is not a burst
  70. Fermi GBM Observations of IceCube-171015A
  71. GRB 171020A: Continued RATIR Optical and NIR Observation
  72. GRB 171020A: TAROT Calern observatory optical observations
  73. GRB 171020A: Swift/UVOT Upper Limits
  74. GRB 171020A: NOT spectroscopic redshift
  75. GRB 171020A: Swift-BAT refined analysis
  76. GRB 171020A: RATIR Optical and NIR Observations
  77. GRB 171020A: Swift-XRT refined Analysis
  78. GRB 171020A: Enhanced Swift-XRT position
  79. GRB 171020A: LT observations
  80. GRB 171020A: Correction of alpha in GCN 22031
  81. GRB 171020A: Confirmation of OT fading
  82. GRB 171020A: Mini-MegaTORTORA upper limits on simultaneous optical emission
  83. GRB 171020A: NOT optical afterglow detection
  84. GRB 171020A: Swift detection of a burst
  85. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  86. GRB 171011B: Insight-HXMT detection
  87. Trigger 780207: Swift triggers again on AXP CXOU J164710.2-455216/PSR J1647-4552
  88. Swift Trigger on AXP CXOU J164710.2-455216/PSR J1647-4552
  89. GRB 171010B: Swift-XRT afterglow detection
  90. GRB 171011B CALET Gamma-Ray Burst Monitor detection
  91. Trigger 779762: Swift detection of Vela X-1
  92. Trigger 779351: Swift detection of Swift J0243.6+6124
  93. Search for counterpart to IceCube-171015A with ANTARES
  94. INTEGRAL SPI-ACS observation of IceCube-171015A
  95. Swift trigger 779171 is probably a noise fluctuation
  96. IceCube-171015A - IceCube observation of a high-energy neutrino candidate event
  97. GRB 171010A: VLA Observations
  98. GRB 171010A: VLA Detection
  99. GRB 171010A: A detection of a radio source by AMI
  100. GRB 171010A : Optical observations from HCT

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