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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"

3041 results found.

  1. IPN triangulation of GRB 201103B (consistent with ZTF20acozryr/AT2020yxz)
  2. GRB 201105B: Fermi GBM observation
  3. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  4. GRB 201026A: Swift detection of a burst
  5. GRB 201020B: follow-up observations with Savelli Telescope
  6. GRB 201024A: Redshift from GTC/OSIRIS
  7. IceCube-201021A: No significant detection in HAWC
  8. IceCube-201021A: One candidate counterpart from the Zwicky Transient Facility
  9. Konus-Wind detection of GRB 201020A
  10. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  11. GRB 201020A: DOAO optical afterglow observations
  12. GRB 201020A: Fermi GBM observation
  13. GRB 201020A: Swift detection of a burst with an optical counterpart.
  14. GRB 201008A: Swift-XRT afterglow detection
  15. GRB 201016A: Fermi GBM detection
  16. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  17. GRB 201013A: FRAM-ORM possible afterglow candidate
  18. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  19. GRB 201013A: Swift detection of a burst
  20. GRB 201008A: Swift-XRT observations
  21. Fermi trigger No 623470566: Global MASTER-Net observations report
  22. Fermi trigger No 623493962: Global MASTER-Net observations report
  23. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  24. IceCube-200929A: No significant detection in HAWC
  25. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  26. IceCube-200926B: No significant detection in HAWC
  27. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  28. IceCube Alert 200926.33: Global MASTER-Net observations report
  29. Fermi GRB 200925A: Global MASTER-Net observations report
  30. Fermi GRB 200924A: Global MASTER-Net observations report
  31. Fermi GRB 200923A: Global MASTER-Net observations report
  32. IceCube Alert 200921.80: Global MASTER-Net observations report
  33. GRB 200922A: Swift/UVOT Detection
  34. IceCube-200921A: no significant detection in HAWC observations
  35. Fermi GRB 200922B: Global MASTER-Net observations report
  36. GRB 200922A: LCO observations
  37. GRB 200920A: Fermi GBM Final Real-time Localization
  38. Fermi GRB 200919C: Global MASTER-Net observations report
  39. Fermi GRB 200919B: Global MASTER-Net observations report
  40. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  41. IPN triangulation of GRB 200916B (short)
  42. IceCube Alert 200914.00: Global MASTER-Net observations report
  43. IPN triangulation of GRB 200907A (short)
  44. Fermi GRB 200908A: Global MASTER-Net observations report
  45. Fermi GRB 200907C: Global MASTER-Net observations report
  46. GRB 200906A: Nanshan/NEXT optical upper limit
  47. Fermi GRB 200903B: Global MASTER-Net observations report
  48. GRB 200901A: Fermi GBM observation
  49. GRB 200901A: Swift detection of a burst
  50. GRB 200829A: Koshka Zeiss-1000 optical observations
  51. Fermi trigger No 620402299: Global MASTER-Net observations report
  52. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  53. IPN triangulation of GRB 200826B
  54. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  55. IPN triangulation of GRB 200815A (short)
  56. GRB 200819A: Kitab, TSHAO optical upper limit
  57. Fermi GRB 200817A: Global MASTER-Net observations report
  58. GRB 200817A: Fermi GBM Final Real-time Localization
  59. Fermi trigger No 619270776: Global MASTER-Net observations report
  60. Fermi GRB 200803A: Global MASTER-Net observations report
  61. Fermi GRB 200802A: Global MASTER-Net observations report
  62. GRB 200802A: Fermi GBM Final Real-time Localization
  63. Fermi GRB 200801A: Global MASTER-Net observations report
  64. Swift Detection of an SGR-like flare from AX J1846.4-0258
  65. Swift GRB200801.84: Global MASTER-Net observations report
  66. Fermi GRB 200716A: Global MASTER-Net observations report
  67. GRB 200716C: Swift detection of a burst with an optical counterpart
  68. Fermi GRB 200714D: Global MASTER-Net observations report
  69. Fermi GRB 200714A: Global MASTER-Net observations report
  70. Fermi trigger No 616370565: Global MASTER-Net observations report
  71. Update of alert from the HAWC Burst Monitor HAWC-200709A
  72. Fermi GRB 200705A: Global MASTER-Net observations report
  73. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  74. GRB 200630A: Swift detection of a burst
  75. Fermi GRB 200626A: Global MASTER-Net observations report
  76. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  77. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  78. Fermi trigger No 614103490: Global MASTER-Net observations report
  79. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  80. GRB 200616B: Fermi GBM Final Real-time Localization
  81. GRB 200615B: MAXI/GSC detection
  82. Baksan Neutrino Observatory Alert 200614.34: Global MASTER-Net observations report
  83. GRB 200614A: Fermi GBM Final Real-time Localization
  84. Swift GRB200612.19: Global MASTER-Net OT detection
  85. Swift GRB200612.19: Global MASTER-Net observations report
  86. Fermi GRB 200604A: Global MASTER-Net observations report
  87. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  88. GRB 200529A: MITSuME Akeno optical upper limits
  89. Fermi GRB 200601A: Global MASTER-Net observations report
  90. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  91. Swift GRB 200528A: Global MASTER-Net observations report
  92. GRB 200524A: CrAO optical observations
  93. GRB 171205A: ATCA observations of late-time radio emission
  94. Fermi GRB 200522B: Global MASTER-Net observations report
  95. GRB 200522B: Fermi GBM Final Real-time Localization
  96. Fermi trigger No 611676654: Global MASTER-Net observations report
  97. GRB 200519A: Swift detection of a burst with an optical afterglow
  98. Fermi trigger No 611434353: Global MASTER-Net observations report
  99. GRB 200517A: MAXI/GSC detection
  100. GRB 200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062) - More Candidates

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