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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"

28677 results found.

  1. GRB 201014A: 3.6m DOT Optical Observations
  2. GRB 201015A: 6 GHz VLA radio afterglow candidate detection
  3. GRB 201013A: 3.6m DOT Optical Observations
  4. GRB 201014A: MMT afterglow detection
  5. GRB 201017A: MITSuME Akeno optical upper limits
  6. GRB 201017A: Swift-BAT refined analysis
  7. GRB 201015A: GROWTH-India Telescope (GIT) upper limit
  8. GRB 201015A: HCT optical photometric follow-up
  9. GRB 201017A: Assy and Mondy optical observations, possible afterglow detection
  10. GRB 201017A: Swift-XRT refined Analysis
  11. GRB 201015A: Xinglong-2.16m optical observations
  12. GRB 201015A: MMT afterglow imaging
  13. GRB 201017A: Fermi GBM detection
  14. GRB 201015A NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  15. GRB 201015A: Assy and Mondy optical observations
  16. GRB 201017A: Xinglong TNT upper limit
  17. GRB 201015A: classification as long GRB
  18. Swift GRB 201017A: Global MASTER-Net observations report
  19. GRB 201015A: FRAM-ORM afterglow detection
  20. Fermi GBM Sub-Threshold Detection of GRB 201015A
  21. GRB 201015A: Swift/UVOT Detection
  22. GRB 201015A: redshift confirmation
  23. GRB 201015A: Swift-XRT refined Analysis
  24. MAGIC observations of GRB 201015A: hint of very high energy gamma-ray signal
  25. GRB 201015A: Swift-BAT refined analysis (a soft short pulse with a tail emission)
  26. IceCube-201014A: No significant detection in HAWC
  27. GRB 201015A: CrAO/ZTSH optical observations
  28. GRB 201014A: Nanshan/NEXT optical observations
  29. GRB 201014A: Lowell Discovery Telescope afterglow imaging
  30. GRB201015A: Nanshan/NEXT early optical observations
  31. Konus-Wind observation of GRB 201013A
  32. GRB 201016A: AstroSat CZTI detection
  33. GRB 201014A: Redshift from GTC/OSIRIS
  34. GRB 201015A: Redshift from GTC/OSIRIS
  35. GRB 201008A: Swift-XRT afterglow detection
  36. GRB 201014A: Swift/UVOT Upper Limits
  37. Fermi GRB 201016B: Global MASTER-Net observations report
  38. GRB 201015A: GOTO confirmation of afterglow detection
  39. GRB 201014A: Swift-XRT refined Analysis
  40. GRB 201015A: NOT optical afterglow confirmation
  41. Swift GRB 201015A: Global MASTER-Net observations report
  42. GRB 201014A: Swift-BAT refined analysis
  43. GRB 201014A (Swift trigger =1000255): CrAO/ZTSH optical afterglow discovery
  44. Swift-BAT trigger 1000255: XRT afterglow detection of GRB 201014A
  45. GRB 201013A: Insight-HXMT/HE detection
  46. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  47. Fermi-LAT Gamma-ray Observations of IceCube-201014A
  48. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  49. GRB 201013A: AstroSat CZTI detection
  50. IceCube-201014A: Not observable by GBM
  51. GRB 201013A: CALET Gamma-Ray Burst Monitor detection
  52. IceCube-201014A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  53. GRB 201013A: Swift-BAT refined analysis
  54. GRB 201013A: Swift/UVOT Upper Limits
  55. Swift GRB 201013A: Global MASTER-Net observations report
  56. GRB 201013A: Swift-XRT refined Analysis
  57. SGR 1830-0645: Swift/UVOT Upper Limits
  58. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  59. GRB 201011A: Fermi GBM detection of a likely Long GRB in the direction of SGR 1830-0645
  60. Fermi trigger No 624139481: AGILE detection
  61. SGR 1830-0645: pre-discovery detection in Swift/BAT
  62. SGR 1830-0645: Swift-BAT refined analysis
  63. GRB 201006A: Chandra upper limit on the X-ray afterglow
  64. SGR 1830-0645 / GRB 201010A: Kitab optical non-detection
  65. IceCube-200929A: JCMT/SCUBA2 observations
  66. IceCube-201007A: No significant detection in HAWC
  67. GRB 201009A: AstroSat CZTI detection
  68. GRB 201008A: Swift-XRT observations
  69. IceCube-200926A: Upper limits from Insight-HXMT Observations
  70. GRB 201008A: Swift ToO observations
  71. IceCube-201007A: Upper limits from Fermi-GBM Observations
  72. GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization
  73. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  74. Swift-XRT observations of IceCube 201007A
  75. IceCube-201007A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  76. GRB 201006A: GROWTH-India Telescope optical upper limit
  77. GRB 201006A: Lowell Discovery Telescope upper limits
  78. GRB 201006A: MITSuME Akeno optical upper limits
  79. Fermi GRB 201007A: Global MASTER-Net observations report
  80. GRB 201006A: Swift-XRT refined Analysis
  81. GRB 201006A: Swift-BAT refined analysis
  82. GRB 201006A: Swift/UVOT Upper Limits
  83. GRB 201006A: Fermi GBM detection
  84. GRB 201006A is likely a short burst
  85. INTEGRAL sub-threshold detection of GRB 201006A
  86. GRB 201001A: Swift/UVOT Upper Limits
  87. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  88. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  89. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  90. GRB 201001A: TSHAO optical upper limit
  91. GRB 201001A: Xinglong-2.16m optical upper limit
  92. GRB 201001A: MITSuME Akeno optical upper limits
  93. IceCube-200926A: JCMT/SCUBA2 observations
  94. IceCube-200929A: No significant detection in HAWC
  95. GRB 201001A: Swift-BAT refined analysis
  96. GRB 201001A: Swift-XRT refined Analysis
  97. GRB 201001A: Fermi GBM observation
  98. Swift-XRT observations of IceCube 200929A
  99. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  100. IceCube-200929A: Upper limits from Fermi-GBM Observations

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