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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"

2921 results found.

  1. GRB 210222B: MASTER OT observation
  2. GRB 210222B: GOTO confirmation of afterglow detection
  3. Swift GRB210222.94: Global MASTER-Net observations report
  4. Fermi GBM Sub-Threshold Detection of GRB 210217A
  5. GRB 210217A: Swift-BAT refined analysis
  6. GRB 210217A: Swift detection of a burst with an optical counterpart
  7. GRB 210208A: 1.3m DFOT Optical upper limit
  8. GRB 210211A: ePESSTO+ NTT optical observations
  9. IceCube Alert 210213.78: Global MASTER-Net observations report
  10. GRB 210204A (ZTF21aagwbjr/AT2021buv): continued CrAO and AbAO optical observations
  11. GRB 210207B: AstroSat CZTI detection
  12. GRB 210207B: Swift-BAT refined analysis
  13. Konus-Wind detection of GRB 210204A (correction to GCN 29415)
  14. GRB 210207A: Fermi GBM Final Real-time Localization
  15. Fermi GRB 210204B: Global MASTER-Net observations report
  16. Fermi GRB 210204A: Global MASTER-Net observations report
  17. GRB 140320B: Swift-XRT refined Analysis
  18. GRB 210104A: DOAO optical afterglow observations
  19. Fermi GRB 210101A: Global MASTER-Net observations report
  20. Fermi trigger No 631118376: Global MASTER-Net observations report
  21. Fermi GRB 201229B: Global MASTER-Net observations report
  22. Fermi GRB 201228B: Global MASTER-Net observations report
  23. GRB 201228B: Fermi GBM Final Real-time Localization
  24. Fermi GRB 201222B: Global MASTER-Net observations report
  25. GRB 201221D: Archival PS1 Imaging of the Putative Host Galaxy
  26. GRB 201221D: candidate optical counterpart from the NOT
  27. GRB 201221A: Swift-BAT refined analysis
  28. GRB 201221D: Prompt enhanced Swift-XRT position
  29. GRB 201221A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 5.7
  30. GRB 201209A: Mondy optical observations, afterglow confirmation
  31. GRB 201214A: 1.3m DFOT, optical upper limits
  32. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  33. Fermi GRB 201214B: Global MASTER-Net observations report
  34. Fermi GRB 201208A: Global MASTER-Net observations report
  35. IceCube-201130A: No significant detection in HAWC
  36. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  37. Swift-XRT observations of IceCube 201130A
  38. GRB 201128A: Swift-BAT refined analysis
  39. GRB 201120B: Fermi GBM Final Localization
  40. ZTF20acozryr/AT2020yxz (GRB 201103B): SAO RAS optical observations
  41. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  42. ZTF20acozryr/AT2020yxz (GRB 201103B): Mondy, Kitab, TSHAO optical observations
  43. Konus-Wind detection of GRB 201105A
  44. GRB 201104C: Fermi GBM Final Real-time Localization
  45. GRB 201104A: Fermi GBM Final Real-time Localization
  46. Swift GRB201027.05: Global MASTER-Net observations report
  47. IceCube-201021A: No neutrino counterpart candidates in ANTARES search
  48. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  49. Alert from the HAWC Burst Monitor HAWC-201019A
  50. Fermi GRB 201020B: Global MASTER-Net observations report
  51. GRB 201015A: Assy and Mondy optical observations
  52. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  53. GRB 201006A: Chandra upper limit on the X-ray afterglow
  54. Fermi GRB 201007A: Global MASTER-Net observations report
  55. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  56. GRB 201006A: Fermi GBM detection
  57. Fermi trigger No 623470566: Global MASTER-Net observations report
  58. Fermi GRB 200925A: Global MASTER-Net observations report
  59. Fermi GRB 200924A: Global MASTER-Net observations report
  60. Fermi GRB 200923A: Global MASTER-Net observations report
  61. IPN triangulation of GRB 200920B (short)
  62. GRB 200917A: GROWTH-India Telescope optical upper limit.
  63. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  64. GRB 200917A: Enhanced Swift-XRT position
  65. GRB 200917A: Swift detection of a burst
  66. Fermi GRB 200916A: Global MASTER-Net observations report
  67. GRB 200916A: Fermi GBM Final Real-time Localization
  68. IceCube Alert 200914.00: Global MASTER-Net observations report
  69. Fermi GRB 200907C: Global MASTER-Net observations report
  70. Fermi GRB 200903C: Global MASTER-Net observations report
  71. GRB 200903B: Insight-HXMT/HE detection
  72. AGILE detection of a burst (AGILE trigger no. 526185273)
  73. Fermi GRB 200903B: Global MASTER-Net observations report
  74. GRB 200903B: Fermi GBM Final Real-time Localization
  75. GRB 200901B: Swift-BAT refined analysis
  76. GRB 200901B: Enhanced Swift-XRT position
  77. GRB 200901B: Swift detection of a burst
  78. GRB 200829A: Liverpool Telescope observations
  79. GRB 200826B: Fermi GBM Final Real-time Localization
  80. GRB 200826A: AstroSat CZTI detection
  81. Fermi GRB 200826A: Global MASTER-Net observations report
  82. Fermi trigger No 619270776: Global MASTER-Net observations report
  83. HAWC alert 200815.26: MASTER optical observations
  84. GRB 200811A: Fermi GBM Final Real-time Localization
  85. GRB 200811A: BALROG localization (Fermi Trigger 618851447 / GRB 200811632)
  86. Fermi GRB 200809B: Global MASTER-Net observations report
  87. Fermi trigger No 618642276: Global MASTER-Net observations report
  88. GRB 200806A: Nanshan/NEXT optical upper limit
  89. GRB 200806A: AbAO optical upper limit
  90. GRB 200803A: AstroSat CZTI detection
  91. LAT GRB200803.15: Global MASTER-Net observations report
  92. Fermi GRB 200803A: Global MASTER-Net observations report
  93. Fermi GRB 200801B: Global MASTER-Net observations report
  94. Fermi GRB 200802A: Global MASTER-Net observations report
  95. Fermi GRB 200801A: Global MASTER-Net observations report
  96. GRB 200723A: GOTO candidate afterglow and host galaxy
  97. Fermi GRB 200723A: Global MASTER-Net observations report
  98. Konus-Wind observation of GRB 200716C: correction to GCN 28147
  99. Konus-Wind observation of GRB 200716C
  100. Fermi GRB 200714D: Global MASTER-Net observations report

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