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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"

3758 results found.

  1. GRB 200623A: Further MMTCam Observations of XRT Source #3
  2. Fermi GRB 200626A: Global MASTER-Net observations report
  3. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  4. GRB 200623A: Swift-XRT observations
  5. GRB 200623A: TNG optical observations
  6. GRB 200623A: Correction to GCN 28013
  7. GRB 200623A: Swift/BAT-GUANO detection and arcminute localization of a short GRB
  8. LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
  9. Swift/UVOT Observations of IceCube 200615A
  10. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  11. Swift-XRT observations of IceCube 200615A
  12. GRB 200615B: MAXI/GSC detection
  13. Fermi GRB 200614A: Global MASTER-Net observations report
  14. Konus-Wind detection of GRB 200605A
  15. GRB 200608A: Swift detection of a burst
  16. Fermi GRB 200607A: Global MASTER-Net observations report
  17. 1RXS J1708−4009: Swift-BAT refined analysis
  18. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  19. Baksan Neutrino Observatory Alert 200601.42: Global MASTER-Net observations report
  20. GRB 200529A: LCO Optical Afterglow Detection
  21. GRB 200528A: CALET Gamma-Ray Burst Monitor detection
  22. GRB 200529A: BOOTES-2/TELMA early optical upper limit
  23. GRB 200524A: SAO RAS optical observations
  24. GRB 200528A: Assy optical upper limit
  25. GRB 200528A: Fermi GBM Observation
  26. GRB 200528A: Nanshan/NEXT optical upper limit
  27. Swift GRB 200528A: Global MASTER-Net observations report
  28. GRB 200528A: MITSuME Akeno optical upper limits
  29. GRB 200528A: Swift detection of a burst
  30. GRB 200528A: Fermi GBM Final Real-time Localization
  31. GRB 200524A: CrAO optical observations
  32. GRB 200525A: Fermi GBM Final Real-time Localization
  33. GRB200521A: ASIM observation
  34. Fermi GRB 200524A: Global MASTER-Net observations report
  35. Fermi GRB 200522B: Global MASTER-Net observations report
  36. Fermi trigger No 611434353: Global MASTER-Net observations report
  37. Swift Detection of a burst from SGR Swift J1818.0-1607
  38. Insight-HXMT's continued observation plan for SGR J1935+2154
  39. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  40. GRB 200506A: AstroSat CZTI detection
  41. GRB 200506A: Fermi GBM Final Real-time Localization
  42. Insight-HXMT detection of a short bright burst from SGR 1935+2154
  43. Geocentric time correction for Insight-HXMT detection of the x-ray counterpart of the FRB by CHIME and STARE2 from SGR 1935+2154
  44. No optical bursts detected from SGR J1935+2154 by 24 fps observations with Tomo-e Gozen
  45. SGR 1935+2154: MASTER optical observations
  46. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154
  47. SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
  48. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  49. Integral GRB200428.61: Global MASTER-Net observations report
  50. A Forest of Bursts from SGR 1935+2154
  51. SGR 1935+2154: AstroSat CZTI detections
  52. high bursting activity of SGR 1935+2154: CGBM observations
  53. SGR 1935+2154 the Insight-HXMT observation plan
  54. IceCube Alert 200425.98: Global MASTER-Net observations report
  55. GRB 200424A: AstroSat CZTI detection
  56. GRB 200415A: ASIM observation
  57. GRB 200410A: Liverpool Telescope First Hour Observations
  58. Fermi GRB 200421A: Global MASTER-Net observations report
  59. Fermi trigger No 608935505: Global MASTER-Net observations report
  60. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  61. Fermi GRB 200415A: Global MASTER-Net observations report
  62. IceCube-200410A: No significant detection in HAWC
  63. Konus-Wind observation of a bright burst from SGR 1935+2154
  64. IceCube Alert 200410.97: Global MASTER-Net observations report
  65. Fermi trigger No 608204639: Global MASTER-Net observations report
  66. Baksan Neutrino Observatory Alert 200409.23: Global MASTER-Net observations report
  67. Fermi GRB 200407B: Global MASTER-Net observations report
  68. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  69. Fermi GRB 200403A: Global MASTER-Net observations report
  70. Fermi GRB 200402C: Global MASTER-Net observations report
  71. GRB 200325B: Optical upper limit
  72. Fermi GRB 200401A: Global MASTER-Net observations report
  73. GRB 200401A: Fermi GBM Final Real-time Localization
  74. GRB 200325B: Mondy continued observations
  75. GRB 200325B: Mondy continued observations
  76. IPN triangulation of GRB 200327A (short)
  77. Fermi trigger No 606918292: Global MASTER-Net observations report
  78. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  79. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  80. LIGO/Virgo S200316bj: Upper limits from CALET observations
  81. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  82. IPN triangulation of GRB 200311A
  83. GRB 200310A: MAXI/GSC detection
  84. GRB 200306C: BOOTES-1 detection of the optical afterglow
  85. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  86. GRB 200228A: AstroSat CZTI detection
  87. LIGO/Virgo S200302c: No transient candidates in CALET observations
  88. Fermi trigger No 604895668: Global MASTER-Net observations report
  89. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  90. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  91. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  92. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  93. Swift GRB 200228B: Global MASTER-Net observations report
  94. GRB 200228B: Fermi GBM observation
  95. IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
  96. GRB 200228A: Fermi GBM observation
  97. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  98. GRB 200228B: Fermi GBM Final Real-time Localization
  99. Fermi trigger No 604565918: Global MASTER-Net observations report
  100. GRB 200228A: BALROG localization (Fermi Trigger 604565918 / GRB 200228291)

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