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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"

3396 results found.

  1. Fermi trigger No 701071944: Global MASTER-Net observations report
  2. GRB 230314A: TURBO Optical Upper Limit
  3. Fermi GRB 230314A: Global MASTER-Net observations report
  4. Further improved IPN localization for GRB 230307A
  5. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  6. GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
  7. Fermi GRB 230307A: Global MASTER-Net observations report
  8. Konus-Wind detection of GRB 230307A
  9. GRB 230228A: VIRT Optical Upper Limit
  10. GRB 230307A: VZLUSAT-2 detection
  11. GRB 230304B: Detection by GRBAlpha
  12. GRB 230301B: Fermi GBM Final Real-time Localization
  13. GRB 230228A: Fermi GBM Observation
  14. Fermi trigger No 699294715: Global MASTER-Net observations report
  15. GRB 230228A: OSN optical upper limit
  16. Fermi trigger No 699311646: Global MASTER-Net observations report
  17. GRB 230228A: Mondy optical upper limit
  18. GRB 230228A: Enhanced Swift-XRT position
  19. GRB 230228A: Nanshan/NEXT optical upper limit
  20. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  21. GRB 230228A: Prompt enhanced Swift-XRT position
  22. GRB 230228A: Swift detection of a possibly short burst
  23. Fermi GRB 230227A: Global MASTER-Net observations report
  24. Fermi trigger No 699029364: Global MASTER-Net observations report
  25. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  26. GRB 230205A: VLA radio afterglow confirmation
  27. GRB 230220A: Correction to GCN 33352
  28. GRB 230217A: 6 GHz VLA observations
  29. GRB 230220A: MAXI/GSC detection
  30. GRB 230217A: Swift-XRT observations
  31. IceCube Alert 230217.87: Global MASTER-Net observations report
  32. Fermi trigger No 697678542: Global MASTER-Net observations report
  33. GRB 230205A: 6 GHz VLA observations
  34. GRB 230209A is not a GRB
  35. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  36. GRB 230209A: Fermi GBM Final Real-time Localization
  37. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  38. Fermi trigger No 697098930: Global MASTER-Net observations report
  39. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  40. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  41. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  42. GRB 230128A: AstroSat CZTI detection
  43. ZTF23aaarlti/AT2023avj: VLA radio detection
  44. GRB 230128A: Fermi GBM Final Real-time Localization
  45. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  46. Fermi GRB 230124A: Global MASTER-Net observations report
  47. Fermi GRB 230118A: Global MASTER-Net observations report
  48. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  49. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  50. GRB 221228A: Fermi GBM Final Real-time Localization
  51. IceCube Alert 221223.32: Global MASTER-Net observations report
  52. GRB 221216A: Detection by VZLUSAT-2
  53. Fermi trigger No 692713692: Global MASTER-Net observations report
  54. Fermi Gamma-ray Burst Monitor triggers 692721536/221214610 and 692713692/221214520 are not GRBs
  55. Fermi GRB 221211A: Global MASTER-Net observations report
  56. IceCube Alert 221210.36: Global MASTER-Net observations report
  57. GRB 221202A: MeerLICHT upper limits
  58. Swift GRB 221201A: Global MASTER-Net observations report
  59. Alert from the HAWC Burst Monitor HAWC-221128A
  60. GRB 221120A: Detection by VZLUSAT-2
  61. Alert from the HAWC Burst Monitor HAWC-221123A
  62. GRB 221120A: AKO Telescope Upper Limits
  63. GRB 221120A: GIT upper limits on optical afterglow
  64. GRB 221120A: Swift detection of a likely short burst
  65. LAT GRB221119.63: Global MASTER-Net observations report
  66. GRB 221115A: Swift/BAT-GUANO detection
  67. GRB 221110A: GRANDMA observations
  68. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 November 9
  69. GRB 221110A: COATLI Second-Epoch Upper Limits
  70. GRB 221110A: GMG upper limit
  71. GRB 221110A: Swift detection of a burst with an optical counterpart
  72. GRB 221028A: Detection by VZLUSAT-2
  73. GRB 221028A: 1.3m DFOT Optical upper limit
  74. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  75. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  76. GRB 221029A: Detection by GRBAlpha
  77. GRB 221028A: CrAO/ZTSh optical upper limit
  78. GRB 221028A: AGILE detection
  79. GRB 221028A: MITSuME Okayama optical upper limits
  80. GRB 221028A: LCOGT Optical Upper Limits
  81. GRB 221027B: COATLI Upper Limits
  82. Swift GRB 221028A: Global MASTER-Net observations report
  83. GRB 221028A: BOOTES-4/MET optical upper limit
  84. GRB 221027B: FRAM-ORM and Ondrejov SBT optical limits
  85. Swift GRB 221027B: Global MASTER-Net observations report
  86. IPN triangulation of GRB 221022C (short)
  87. GRB 221023A: AGILE/GRID analysis
  88. IPN triangulation of GRB 221022B (long)
  89. GRB 221024A: Swift detection of a burst
  90. Fermi GBM trigger 687320613 / 221013100 (GRB 221013B) is not a GRB
  91. GRB 221013B: Swift/BAT-GUANO detection
  92. SGR 1935+2154: Bursting activity detected by VZLUSAT-2
  93. IPN triangulation of GRB 221017A (long)
  94. MAXI GRB221017.24: Global MASTER-Net observations report
  95. MAXI GRB 221006A: Redshifts of the possible host galaxies
  96. GRB 221013B: Fermi GBM Final Real-time Localization
  97. Integral GRB221012.98: Global MASTER-Net observations report
  98. Afterglow limits of GRB 221006A from OHP
  99. Fermi trigger No 687205006: Global MASTER-Net observations report
  100. GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger

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