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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"

28050 results found.

  1. IceCube Alert 200921.80: Global MASTER-Net observations report
  2. IceCube-200921A: Upper limits from a search for additional neutrino events in IceCube
  3. GRB 200922A: Swift-BAT refined analysis
  4. GRB 200922A: Swift/UVOT Detection
  5. Fermi-LAT Gamma-ray Observations of IceCube-200921A and detection of a new gamma-ray source, Fermi J1256.9+2630
  6. IceCube-200921A: no significant detection in HAWC observations
  7. GRB 200922A: LCO observations
  8. GRB 200922A: Swift-XRT refined Analysis
  9. GRB 200917A: Swift/UVOT Upper Limits
  10. GRB 200922A: Enhanced Swift-XRT position
  11. GRB 200919C: Insight-HXMT/HE detection
  12. GRB 200922A: Swift detection of a burst with possible optical counterpart
  13. IceCube-200921A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  14. GRB 200914A: Swift-XRT further observations
  15. GRB 200919A: CrAO/ZTSh early optical upper limit
  16. GRB 200919A: Swift-BAT refined analysis
  17. IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
  18. IceCube-200916A: Upper limits from a search for additional neutrino events in IceCube
  19. GRB 200916B: AstroSat CZTI detection
  20. GRB 200917A: GROWTH-India Telescope optical upper limit.
  21. Swift-XRT observations of IceCube 200916A
  22. IceCube-200916A: No significant detection in HAWC
  23. GRB 200917A: Swift-BAT refined analysis
  24. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  25. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  26. GRB 200917A: Swift-XRT refined Analysis
  27. IceCube-200916A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  28. IPN triangulation of GRB 200916B (short)
  29. Fermi-LAT Gamma-ray Observations of IceCube-200916A
  30. GRB 200917A: Enhanced Swift-XRT position
  31. GRB 200917A: Swift detection of a burst
  32. Swift-XRT observations of IceCube 200911A
  33. GRB 200914A: Swift-XRT observations
  34. GRB 200914A: Fermi GBM observation
  35. IceCube-200911A: No significant detection in HAWC
  36. Fermi-LAT Gamma-ray Observations of IceCube-200911A and detection of a new gamma-ray source, Fermi J0330.1+3743
  37. GRB 200914A : A long GRB detected by INTEGRAL
  38. GRB 200914A: BALROG localization (Fermi Trigger 621780515 / GRB 200914534)
  39. IceCube-200911A: No neutrino counterpart candidates in ANTARES search
  40. IceCube-200911A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  41. IPN triangulation of GRB 200907A (short)
  42. GRB 200909B: Swift-BAT refined analysis
  43. GRB 200909A: AstroSat CZTI detection
  44. GRB 200829A: T100 observations
  45. GRB 200909A: BALROG localization (Fermi Trigger 621316887 / GRB 200909168)
  46. GRB 200907B: Swift/UVOT Upper Limits
  47. GRB 200907B: Swift-BAT refined analysis
  48. GRB 200907B: AstroSat CZTI detection
  49. GRB 200907B: Swift-XRT refined Analysis
  50. GRB 200907B: MITSuME Okayama optical upper limits
  51. GRB 200907B: Enhanced Swift-XRT position
  52. Correction to GCN 28387: GRB 200907B GROWTH-India optical upper limit
  53. GRB200907A: GROWTH-India optical upper limit
  54. Fermi GRB 200906A: Global MASTER-Net observations report
  55. GRB 200907B: Swift detection of a short burst
  56. GRB 200906A: EMIR/GTC NIR upper limit
  57. GRB 200906A: Swift-BAT refined analysis
  58. GRB 200906A: Swift/UVOT Upper Limits
  59. GRB 200906A: GROWTH-India Telescope (GIT) optical r band upper limit
  60. GRB 200906A: Swift-XRT refined Analysis
  61. GRB 200906A: Fermi GBM detection
  62. GRB 200906A: Enhanced Swift-XRT position
  63. GRB 200906A: Nanshan/NEXT optical upper limit
  64. GRB 200906A: Swift detection of a burst
  65. GRB 200903E: AstroSat CZTI detection
  66. GRB 200903D: MAXI/GSC detection
  67. GRB 200903A: Swift-BAT refined analysis
  68. GRB 200829A: optical observations, a light curve in R-filter
  69. GRB 200903B: Insight-HXMT/HE detection
  70. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  71. GRB 200901B: Swift-XRT refined Analysis
  72. INTEGRAL Weak#8699: AROMA-N Optical Observation
  73. GRB 200901B: Swift-BAT refined analysis
  74. GRB 200901A: Swift-BAT refined analysis
  75. GRB 200901B: Swift/UVOT Detection
  76. GRB 200901A: Swift/UVOT Detection
  77. GRB 200901A: Swift-XRT refined Analysis
  78. GRB 200901A: Fermi GBM observation
  79. GRB 200901B: Enhanced Swift-XRT position
  80. GRB 200829A: Swift/UVOT-XRT photometric redshift
  81. GRB 200901B: Swift detection of a burst
  82. GRB 200901A: Swift-XRT observations
  83. GRB 200901A: Swift detection of a burst
  84. GRB 200829A: Koshka Zeiss-1000 optical observations
  85. GRB 200829A: Liverpool Telescope observations
  86. GRB 200829A: Continued Nanshan/NEXT optical observations
  87. GRB 200829A: Kitab optical upper limit
  88. GRB 200829A: further SAO RAS optical observations
  89. GRB 200829A: Swift-BAT refined analysis
  90. GRB 200829A: Nanshan/NEXT optical observations
  91. GRB 200829A: SAO RAS optical observations
  92. GRB 200830A: BALROG localization (Fermi Trigger 620474063 / GRB 200830413)
  93. GRB 200826A
  94. GRB 200829A: Swift-XRT refined Analysis
  95. GRB 200829A: Enhanced Swift-XRT position
  96. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  97. GRB 200829A: Swift/UVOT Detection
  98. GRB 200829A: TSHAO optical observations
  99. GRB 200829A: Swift detection of a burst with an optical afterglow
  100. GRB 200826A: Kitab optical observations

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