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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"

27394 results found.

  1. MAXI GRB211218.04: Global MASTER-Net observations report
  2. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  3. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  4. IceCube-211216A: Upper limits from a search for additional neutrino events in IceCube
  5. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  6. GRB 211217A: GECAM detection
  7. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  8. GRB 211216B: GECAM detection
  9. IceCube-211216A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  10. GRB 211211A: TNG NIR observations
  11. GRB 211216A: GECAM detection
  12. GRB 211216A: BALROG localization (Fermi Trigger 661329957 / GRB 211216282)
  13. GRB 211211A - Gemini K-band detection
  14. GRB 211211A: SAO RAS optical observations
  15. GRB 211211A: AbAO optical observations
  16. GRB 211211A: GMG upper limit
  17. Chandra observation of GW170817 at ~1575 days since merger (all epochs)
  18. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  19. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  20. GRB 211211A: HCT and GIT optical follow up observations
  21. IceCube-211208A: No neutrino counterpart detected with ANTARES
  22. GRB 211211A: Swift/UVOT detection
  23. GRB 211211B: GECAM detection
  24. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  25. GRB 211211A: MITSuME Akeno optical observation
  26. GRB 211211A: LCO Optical Observations
  27. GRB 211211A: Nanshan/NEXT optical observations
  28. GRB 211211A: Swift-XRT refined Analysis
  29. GRB 211211A: Fermi GBM observation
  30. GRB 211211A: Swift-BAT refined analysis
  31. GRB 211211A: Enhanced Swift-XRT position
  32. GRB 211207A: Swift/UVOT Detection
  33. GRB 211211A: Swift detection of a bright burst
  34. IceCube-211208A: No significant detection in HAWC
  35. AMON NuEm-211020A: No neutrino counterpart detected with ANTARES
  36. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  37. IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube
  38. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  39. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  40. GRB 211207A: Swift-BAT refined analysis
  41. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  42. GRB 211207A: Swift-XRT refined Analysis
  43. GRB 211207A: Enhanced Swift-XRT position
  44. GRB 211207A: Swift detection of a burst with an optical counterpart
  45. GRB 211206A: AstroSat CZTI detection
  46. GRB 211206B: AstroSat CZTI detection
  47. GRB 211204C: AstroSat CZTI detection
  48. IPN triangulation of GRB 211204C
  49. GRB 211206A: Swift/BAT-GUANO detection outside the coded FOV
  50. GRB 211204C: Swift/BAT-GUANO detection outside the coded FOV
  51. GRB 211204C: GECAM detection
  52. GRB 211124A: Fermi GBM Observation
  53. Fermi GBM Upper limits for GRB 211203A
  54. GRB 211203A: Swift detection of a burst
  55. GRB 211201A: Swift/BAT-GUANO detection likely outside the coded FOV
  56. GRB 211106A: Second HST Observation
  57. GRB 211201A: Fermi GBM Final Real-time Localization
  58. IceCube-211125A: No significant detection in HAWC
  59. GRB 211130A: BALROG localization (Fermi Trigger 659978192 / GRB 211130636)
  60. GRB 211129A: Swift-BAT refined analysis
  61. GRB 211129A: Swift-XRT refined Analysis
  62. GRB 211129A: Swift/UVOT Upper Limits
  63. GRB 211106A: HST Observations
  64. GRB 211106A: Chandra Observations
  65. IceCube-Cascade 211128A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-211125A: Upper limits from a search for additional neutrino events in IceCube
  67. GRB 211129A: Fermi GBM observation
  68. GRB 211129A: Nanshan/NEXT optical upper limit
  69. GRB 211129A: Enhanced Swift-XRT position
  70. IPN triangulation of GRB 211118A
  71. GRB 211129A: MITSuME Akeno optical upper limits
  72. GRB 211129A: Swift detection of a burst
  73. IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  74. GRB 211023A: Xinglong 2.16m optical observations
  75. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  76. GRB 211120548: Fermi GBM observation
  77. Konus-Wind detection of GRB 211120A
  78. IceCube-211125A: No neutrino counterpart detected with ANTARES
  79. GRB 211118A: Fermi GBM detection
  80. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  81. IceCube-211123A: Upper limits from a search for additional neutrino events in IceCube
  82. IPN triangulation of GRB 211124A (short)
  83. HAWC-211123A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  84. GRB 211124A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  85. IceCube Alert 211123.60: Global MASTER-Net observations report
  86. HAWC-211123A: No neutrino counterpart detected with ANTARES
  87. GRB 211023B: LBT likely spectroscopic redshift of the host galaxy
  88. Alert from the HAWC Burst Monitor HAWC-211123A
  89. GRB 211120A: AstroSat CZTI detection
  90. Fermi trigger No 659106591: Global MASTER-Net observations report
  91. GRB 211120B: Swift/BAT-GUANO detection outside the coded FOV
  92. GRB 211120A: GECAM detection
  93. GRB 211118A: AstroSat CZTI detection
  94. GRB 211023A: optical observations and photometric evidence of supernova
  95. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  96. GRB211118A: Swift/BAT-GUANO detection outside the coded FOV
  97. Search for counterpart to IceCube-211117A with ANTARES
  98. IceCube-211116A: Upper limits from a search for additional neutrino events in IceCube
  99. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  100. IceCube-211116A: No neutrino counterpart detected with ANTARES

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