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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"

28059 results found.

  1. GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  2. GRB 200925B: Swift-XRT refined Analysis
  3. GRB 200925B: Swift/UVOT Detection
  4. GRB 200925B: Swift-BAT refined analysis
  5. GRB 200922A: Chilescope optical observations
  6. GRB 200925B: Enhanced Swift-XRT position
  7. GRB 200925B: OSN Afterglow Candidate Discovery
  8. GRB 200925B: Swift detection of a burst
  9. GRB 200922A: Insight-HXMT/HE detection
  10. IceCube Alert 200921.80: Global MASTER-Net observations report
  11. IceCube-200921A: Upper limits from a search for additional neutrino events in IceCube
  12. GRB 200922A: Swift-BAT refined analysis
  13. GRB 200922A: Swift/UVOT Detection
  14. Fermi-LAT Gamma-ray Observations of IceCube-200921A and detection of a new gamma-ray source, Fermi J1256.9+2630
  15. IceCube-200921A: no significant detection in HAWC observations
  16. GRB 200922A: LCO observations
  17. GRB 200922A: Swift-XRT refined Analysis
  18. GRB 200917A: Swift/UVOT Upper Limits
  19. GRB 200922A: Enhanced Swift-XRT position
  20. GRB 200919C: Insight-HXMT/HE detection
  21. GRB 200922A: Swift detection of a burst with possible optical counterpart
  22. IceCube-200921A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  23. GRB 200914A: Swift-XRT further observations
  24. GRB 200919A: CrAO/ZTSh early optical upper limit
  25. GRB 200919A: Swift-BAT refined analysis
  26. IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
  27. IceCube-200916A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB 200916B: AstroSat CZTI detection
  29. GRB 200917A: GROWTH-India Telescope optical upper limit.
  30. Swift-XRT observations of IceCube 200916A
  31. IceCube-200916A: No significant detection in HAWC
  32. GRB 200917A: Swift-BAT refined analysis
  33. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  34. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  35. GRB 200917A: Swift-XRT refined Analysis
  36. IceCube-200916A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  37. IPN triangulation of GRB 200916B (short)
  38. Fermi-LAT Gamma-ray Observations of IceCube-200916A
  39. GRB 200917A: Enhanced Swift-XRT position
  40. GRB 200917A: Swift detection of a burst
  41. Swift-XRT observations of IceCube 200911A
  42. GRB 200914A: Swift-XRT observations
  43. GRB 200914A: Fermi GBM observation
  44. IceCube-200911A: No significant detection in HAWC
  45. Fermi-LAT Gamma-ray Observations of IceCube-200911A and detection of a new gamma-ray source, Fermi J0330.1+3743
  46. GRB 200914A : A long GRB detected by INTEGRAL
  47. GRB 200914A: BALROG localization (Fermi Trigger 621780515 / GRB 200914534)
  48. IceCube-200911A: No neutrino counterpart candidates in ANTARES search
  49. IceCube-200911A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  50. IPN triangulation of GRB 200907A (short)
  51. GRB 200909B: Swift-BAT refined analysis
  52. GRB 200909A: AstroSat CZTI detection
  53. GRB 200829A: T100 observations
  54. GRB 200909A: BALROG localization (Fermi Trigger 621316887 / GRB 200909168)
  55. GRB 200907B: Swift/UVOT Upper Limits
  56. GRB 200907B: Swift-BAT refined analysis
  57. GRB 200907B: AstroSat CZTI detection
  58. GRB 200907B: Swift-XRT refined Analysis
  59. GRB 200907B: MITSuME Okayama optical upper limits
  60. GRB 200907B: Enhanced Swift-XRT position
  61. Correction to GCN 28387: GRB 200907B GROWTH-India optical upper limit
  62. GRB200907A: GROWTH-India optical upper limit
  63. Fermi GRB 200906A: Global MASTER-Net observations report
  64. GRB 200907B: Swift detection of a short burst
  65. GRB 200906A: EMIR/GTC NIR upper limit
  66. GRB 200906A: Swift-BAT refined analysis
  67. GRB 200906A: Swift/UVOT Upper Limits
  68. GRB 200906A: GROWTH-India Telescope (GIT) optical r band upper limit
  69. GRB 200906A: Swift-XRT refined Analysis
  70. GRB 200906A: Fermi GBM detection
  71. GRB 200906A: Enhanced Swift-XRT position
  72. GRB 200906A: Nanshan/NEXT optical upper limit
  73. GRB 200906A: Swift detection of a burst
  74. GRB 200903E: AstroSat CZTI detection
  75. GRB 200903D: MAXI/GSC detection
  76. GRB 200903A: Swift-BAT refined analysis
  77. GRB 200829A: optical observations, a light curve in R-filter
  78. GRB 200903B: Insight-HXMT/HE detection
  79. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  80. GRB 200901B: Swift-XRT refined Analysis
  81. INTEGRAL Weak#8699: AROMA-N Optical Observation
  82. GRB 200901B: Swift-BAT refined analysis
  83. GRB 200901A: Swift-BAT refined analysis
  84. GRB 200901B: Swift/UVOT Detection
  85. GRB 200901A: Swift/UVOT Detection
  86. GRB 200901A: Swift-XRT refined Analysis
  87. GRB 200901A: Fermi GBM observation
  88. GRB 200901B: Enhanced Swift-XRT position
  89. GRB 200829A: Swift/UVOT-XRT photometric redshift
  90. GRB 200901B: Swift detection of a burst
  91. GRB 200901A: Swift-XRT observations
  92. GRB 200901A: Swift detection of a burst
  93. GRB 200829A: Koshka Zeiss-1000 optical observations
  94. GRB 200829A: Liverpool Telescope observations
  95. GRB 200829A: Continued Nanshan/NEXT optical observations
  96. GRB 200829A: Kitab optical upper limit
  97. GRB 200829A: further SAO RAS optical observations
  98. GRB 200829A: Swift-BAT refined analysis
  99. GRB 200829A: Nanshan/NEXT optical observations
  100. GRB 200829A: SAO RAS optical observations

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