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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"

27402 results found.

  1. GRB 200412B: continued Tautenburg observations
  2. GRB 200416A: Fermi GBM observation
  3. GRB 200416A: Swift detection of a burst with an optical afterglow
  4. GRB 200415A: Fermi GBM observation
  5. IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
  6. GRB 200412B: Mondy optical observations
  7. GRB 200412B: continued Tautenburg observations
  8. GRB 200415A: BALROG localization (Fermi Trigger 608633290 / GRB 200415367)
  9. GRB 200410A: Swift-BAT refined analysis
  10. GRB 200412B: Tautenburg observations
  11. GRB 200412B: contunued AbAO optical observations
  12. GRB 200412B: SAO RAS observations of OT
  13. IceCube-200410A: No significant detection in HAWC
  14. GRB 200412B: Tautenburg observations
  15. GRB 200412B: AbAO optical observations
  16. GRB 200412B: Insight-HXMT/HE detection
  17. IceCube-200410A : Upper limits from Insight-HXMT/HE observations
  18. GRB 200412B: Swift-XRT afterglow detection
  19. Fermi GRB 200412A: Global MASTER-Net observations report
  20. GRB 200412B: Fermi GBM detection
  21. IceCube-200410A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 200412A: Fermi GBM detection
  23. GRB 200412B: BALROG localization (Fermi Trigger 608375325 / GRB 200412381)
  24. GRB 200412A: BALROG localization (Fermi Trigger 608367436 / GRB 200412290)
  25. GRB 200411A: Swift-BAT refined analysis
  26. Fermi-LAT Gamma-ray Observations of IceCube-200410A
  27. GRB 200411A: Swift-XRT refined Analysis
  28. GRB 200411A: Swift/UVOT Upper Limits
  29. GRB 200411A: Enhanced Swift-XRT position
  30. IceCube-200410A: Possible associated excess in INTEGRAL SPI-ACS prompt observation
  31. GRB 200411A: Swift detection of a short burst
  32. GRB 200410A: Swift/UVOT Detection
  33. LIGO/Virgo S200225q: Swift XRT observations, 1 X-ray sources
  34. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  35. GRB 200410A: Swift-XRT refined Analysis
  36. GRB 200410A: Enhanced Swift-XRT position
  37. GRB 200409A: Swift-BAT refined analysis
  38. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  39. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  40. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  41. Fermi GBM Sub-Threshold Detection of GRB 200409A
  42. GRB 200409A: Swift-XRT refined Analysis
  43. GRB 200409A: Enhanced Swift-XRT position
  44. GRB 200409A: Swift detection of a burst with an optical counterpart
  45. GRB 200405B: LCO Optical Upper Limits
  46. GRB 200405B: Swift-XRT observations
  47. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  48. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  49. LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
  50. LIGO/Virgo S200311bg: Upper limits from Konus-Wind observations
  51. LIGO/Virgo S200302c: Upper limits from Konus-Wind observations
  52. LIGO/Virgo S200225q: Upper limits from Konus-Wind observations
  53. LIGO/Virgo S200224ca: Upper limits from Konus-Wind observations
  54. GRB 200402B: BALROG localization (Fermi Trigger 607537834 / GRB 200402688)
  55. GRB 200402A: BALROG localization (Fermi Trigger 607513182 / GRB 200402403)
  56. GRB 200325B: Optical upper limit
  57. GRB 200325B: further Swift-XRT observations
  58. GRB 200401A: Fermi GBM Final Real-time Localization
  59. GRB 200325B: Tautenburg observations
  60. IPN triangulation of GRB 200327A (short)
  61. GRB 200327A: AGILE/MCAL observations
  62. GRB 200325B: Fermi GBM observation
  63. GRB 200325B: Swift-XRT and UVOT observations
  64. GRB 200325B: LCO Optical Detection
  65. GRB 200326B: AstroSat LAXPC detection
  66. GRB 200325A: Fermi GBM observation
  67. GRB 200325B: Mondy and CrAO observations, Master MASTER OT J111012.51+274912.8 confirmation
  68. GRB 200324A: AROMA-N Optical Observation
  69. GRB 200324A, Swift-BAT refined analysis
  70. GRB 200324A:: TSHAO optical upper limit
  71. GRB 200324A: Swift/UVOT Upper Limits
  72. GRB 200325A: AGILE/MCAL observations
  73. GRB 200324A: LCO Optical Upper Limit
  74. GRB 200324A: Swift-XRT refined Analysis
  75. GRB 200324A: Konkoly Obs. optical upper limit
  76. GRB 200324A: NOT optical upper limit
  77. GRB 200324A: Tautenburg observations
  78. GRB 200324A: Enhanced Swift-XRT position
  79. GRB 200324A: Swift detection of a burst
  80. GRB 200323A: Fermi GBM detection
  81. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  82. LIGO/Virgo S200316bj: Updated Sky Localization and EM Bright Classification
  83. GRB 200320B: MAXI/GSC detection
  84. GRB 200319A: BALROG localization (Fermi Trigger 606296685 / GRB 200319323)
  85. Chandra observations of GW170817 at 2.5 years since merger (All epochs 4 of 4)
  86. GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
  87. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  88. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  89. Konus-Wind observation of GRB 200313B
  90. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  91. LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
  92. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  93. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  94. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  95. LIGO/Virgo S200213t: Continued Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  96. LIGO/Virgo S200316bj: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  97. LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
  98. LIGO/Virgo S200316bj: upper limits from AGILE/MCAL observations
  99. LIGO/Virgo S200316bj: Upper limits from Fermi-GBM Observations
  100. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations

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