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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"

28057 results found.

  1. GRB 200716A: BALROG localization (Fermi Trigger 616555602 / GRB 200716060)
  2. GRB 200715A : A long GRB detected by INTEGRAL
  3. GRB 200714E: Fermi GBM observation
  4. GRB 200714E: Swift-XRT observations
  5. GRB 200714E: BALROG localization (Fermi Trigger 616444510 / GRB 200714774)
  6. GRB 200713A: Swift-BAT refined analysis
  7. GRB 200711A: Insight-HXMT/HE detection
  8. GRB 200713A: Swift-XRT refined Analysis
  9. GRB 200713A: Enhanced Swift-XRT position
  10. GRB 200713A: Swift detection of a burst
  11. GRB 200711A: AbAO optical upper limit
  12. GRB 200711A: Swift/UVOT Upper Limits
  13. GRB 200711A: Swift-BAT refined analysis
  14. GRB 200711A: Swift-XRT refined Analysis
  15. GRB 200711A: Fermi GBM detection
  16. GRB 200711A: Swift detection of a burst
  17. Update of alert from the HAWC Burst Monitor HAWC-200709A
  18. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  19. HAWC-200907A: No Neutrino Counterpart detected with ANTARES
  20. GRB 200709B: Swift-XRT observations
  21. GRB 200707A: Insight-HXMT/HE detection
  22. GRB 200704A: Insight-HXMT/HE detection
  23. Fermi-LAT-ANTARES 200407a Coincidence
  24. GRB 200703B: Insight-HXMT/HE detection
  25. GRB 200703B: AstroSat CZTI detection
  26. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  27. GRB 200701A: Swift-BAT refined analysis
  28. Fermi-GBM Sub-Threshold Detection of GRB 200701A
  29. GRB 200701A: Swift detection of a burst
  30. GRB 200630A: Swift-BAT refined analysis
  31. GRB 200630A: Swift/UVOT Upper Limits
  32. GRB 200630A: Swift-XRT refined Analysis
  33. GRB 200623A: Swift XRT further observations
  34. GRB 200630A: Fermi GBM detection
  35. GRB 200629A: AstroSat CZTI detection
  36. GRB 200630A: Enhanced Swift-XRT position
  37. GRB 200630A: Swift detection of a burst
  38. GRB 200629A: BALROG localization (Fermi Trigger 615127794 / GRB 200629535)
  39. Konus-Wind detection of short/hard GRB 200623B
  40. GRB 200623A: LBT optical observations
  41. GRB 200623A : SMA observations at Swift/XRT Source #3
  42. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  43. GRB 200623A: MMT observations at XRT Source #3
  44. GRB 200623A: Swift/UVOT Upper Limits
  45. IPN triangulation of GRB 200623B (short)
  46. GRB 200623A: Swift-XRT observations
  47. GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
  48. GRB 200623A: TNG optical observations
  49. GRB 200623A: AbAO afterglow candidate within XRT #2
  50. IceCube-200620A: No significant detection in HAWC
  51. IceCube-200620A: Upper limits from a search for additional neutrino events in IceCube
  52. Fermi-LAT Gamma-ray Observations of IceCube-200620A
  53. IceCube-200620A: No ANTARES neutrino counterpart
  54. GRB 200613A: R-band observations from HCT
  55. GRB 200613A: Further Liverpool Telescope observations
  56. GRB 200619B: AstroSat CZTI detection
  57. GRB 200619A: Fermi GBM observation
  58. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  59. LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
  60. LIGO/Virgo MS200618bx: Retraction of a test binary neutron star candidate
  61. LIGO/Virgo MS200618bq: Retraction of a test binary neutron star candidate
  62. GRB 200619A: Insight-HXMT/HE detection
  63. GRB 200613A: SAO RAS optical observations
  64. GRB 200617A: Insight-HXMT/HE detection
  65. IceCube-200530A - SN2020lls likely unrelated
  66. Swift/UVOT Observations of IceCube 200615A
  67. LIGO/Virgo MS200614ct: Identification of a test binary black hole candidate
  68. Swift-XRT observations of IceCube 200615A
  69. IceCube-200615A: No significant detection in HAWC
  70. GRB 200613A: Jet-break from Xinglong-2.16m optical observations
  71. Fermi-LAT Gamma-ray Observations of IceCube-200615A
  72. IceCube-200614A: No significant detection in HAWC
  73. IceCube-200615A: Upper limits from a search for additional neutrino events in IceCube
  74. Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
  75. LIGO/Virgo MS200615ce: Identification of a test binary black hole candidate
  76. GRB 200613A: CALET Gamma-Ray Burst Monitor detection
  77. LIGO/Virgo MS200614bz: Test Identification of a binary neutron star candidate
  78. GRB 200613A: MITSuME Akeno optical upper limits
  79. GRB 200615B: MAXI/GSC detection
  80. IceCube-200614A: Upper limits from a search for additional neutrino events in IceCube
  81. IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  82. IceCube-200614A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  83. LIGO/Virgo MS200615h: Retraction of a test binary neutron star candidate
  84. GRB 200613A: Continued Xinglong-2.16m optical observations
  85. GRB 200613A: Swift/UVOT Detection
  86. GRB 200613A: Xinglong-2.16m optical observations
  87. GRB 200613A: Liverpool Telescope observations
  88. GRB 200613A: Swift-XRT afterglow detection
  89. GRB 200612A: Fermi GBM detection
  90. GRB 200613A: Fermi GBM observation
  91. GRB 200612A: Swift/UVOT Upper Limits
  92. Baksan Neutrino Observatory Alert 200611.74: Global MASTER-Net observations report
  93. BALROG localization (Fermi Trigger 613719013 / GRB 200613229)
  94. GRB 200612A: Swift-BAT refined analysis
  95. GRB 200612A: Swift-XRT refined Analysis
  96. Konus-Wind observation of ultra-long GRB 200612A
  97. GRB 200612A: Enhanced Swift-XRT position
  98. Swift GRB200612.19: Global MASTER-Net OT detection
  99. GRB 200612A: Swift detection of a burst
  100. GRB 200609A: Insight-HXMT/HE detection

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