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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"

3759 results found.

  1. GRB 200629A: AstroSat CZTI detection
  2. GRB 200623A: Further MMTCam Observations of XRT Source #3
  3. Fermi GRB 200626A: Global MASTER-Net observations report
  4. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  5. GRB 200623A: Swift-XRT observations
  6. GRB 200623A: TNG optical observations
  7. GRB 200623A: Correction to GCN 28013
  8. GRB 200623A: Swift/BAT-GUANO detection and arcminute localization of a short GRB
  9. LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
  10. Swift/UVOT Observations of IceCube 200615A
  11. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  12. Swift-XRT observations of IceCube 200615A
  13. GRB 200615B: MAXI/GSC detection
  14. Fermi GRB 200614A: Global MASTER-Net observations report
  15. Konus-Wind detection of GRB 200605A
  16. GRB 200608A: Swift detection of a burst
  17. Fermi GRB 200607A: Global MASTER-Net observations report
  18. 1RXS J1708−4009: Swift-BAT refined analysis
  19. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  20. Baksan Neutrino Observatory Alert 200601.42: Global MASTER-Net observations report
  21. GRB 200529A: LCO Optical Afterglow Detection
  22. GRB 200528A: CALET Gamma-Ray Burst Monitor detection
  23. GRB 200529A: BOOTES-2/TELMA early optical upper limit
  24. GRB 200524A: SAO RAS optical observations
  25. GRB 200528A: Assy optical upper limit
  26. GRB 200528A: Fermi GBM Observation
  27. GRB 200528A: Nanshan/NEXT optical upper limit
  28. Swift GRB 200528A: Global MASTER-Net observations report
  29. GRB 200528A: MITSuME Akeno optical upper limits
  30. GRB 200528A: Swift detection of a burst
  31. GRB 200528A: Fermi GBM Final Real-time Localization
  32. GRB 200524A: CrAO optical observations
  33. GRB 200525A: Fermi GBM Final Real-time Localization
  34. GRB200521A: ASIM observation
  35. Fermi GRB 200524A: Global MASTER-Net observations report
  36. Fermi GRB 200522B: Global MASTER-Net observations report
  37. Fermi trigger No 611434353: Global MASTER-Net observations report
  38. Swift Detection of a burst from SGR Swift J1818.0-1607
  39. Insight-HXMT's continued observation plan for SGR J1935+2154
  40. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  41. GRB 200506A: AstroSat CZTI detection
  42. GRB 200506A: Fermi GBM Final Real-time Localization
  43. Insight-HXMT detection of a short bright burst from SGR 1935+2154
  44. Geocentric time correction for Insight-HXMT detection of the x-ray counterpart of the FRB by CHIME and STARE2 from SGR 1935+2154
  45. No optical bursts detected from SGR J1935+2154 by 24 fps observations with Tomo-e Gozen
  46. SGR 1935+2154: MASTER optical observations
  47. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154
  48. SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
  49. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  50. Integral GRB200428.61: Global MASTER-Net observations report
  51. A Forest of Bursts from SGR 1935+2154
  52. SGR 1935+2154: AstroSat CZTI detections
  53. high bursting activity of SGR 1935+2154: CGBM observations
  54. SGR 1935+2154 the Insight-HXMT observation plan
  55. IceCube Alert 200425.98: Global MASTER-Net observations report
  56. GRB 200424A: AstroSat CZTI detection
  57. GRB 200415A: ASIM observation
  58. GRB 200410A: Liverpool Telescope First Hour Observations
  59. Fermi GRB 200421A: Global MASTER-Net observations report
  60. Fermi trigger No 608935505: Global MASTER-Net observations report
  61. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  62. Fermi GRB 200415A: Global MASTER-Net observations report
  63. IceCube-200410A: No significant detection in HAWC
  64. Konus-Wind observation of a bright burst from SGR 1935+2154
  65. IceCube Alert 200410.97: Global MASTER-Net observations report
  66. Fermi trigger No 608204639: Global MASTER-Net observations report
  67. Baksan Neutrino Observatory Alert 200409.23: Global MASTER-Net observations report
  68. Fermi GRB 200407B: Global MASTER-Net observations report
  69. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  70. Fermi GRB 200403A: Global MASTER-Net observations report
  71. Fermi GRB 200402C: Global MASTER-Net observations report
  72. GRB 200325B: Optical upper limit
  73. Fermi GRB 200401A: Global MASTER-Net observations report
  74. GRB 200401A: Fermi GBM Final Real-time Localization
  75. GRB 200325B: Mondy continued observations
  76. GRB 200325B: Mondy continued observations
  77. IPN triangulation of GRB 200327A (short)
  78. Fermi trigger No 606918292: Global MASTER-Net observations report
  79. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  80. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  81. LIGO/Virgo S200316bj: Upper limits from CALET observations
  82. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  83. IPN triangulation of GRB 200311A
  84. GRB 200310A: MAXI/GSC detection
  85. GRB 200306C: BOOTES-1 detection of the optical afterglow
  86. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  87. GRB 200228A: AstroSat CZTI detection
  88. LIGO/Virgo S200302c: No transient candidates in CALET observations
  89. Fermi trigger No 604895668: Global MASTER-Net observations report
  90. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  91. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  92. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  93. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  94. Swift GRB 200228B: Global MASTER-Net observations report
  95. GRB 200228B: Fermi GBM observation
  96. IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
  97. GRB 200228A: Fermi GBM observation
  98. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  99. GRB 200228B: Fermi GBM Final Real-time Localization
  100. Fermi trigger No 604565918: Global MASTER-Net observations report

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