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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

8490 results found.

  1. IceCube-200512A: No Candidate Counterparts from the Zwicky Transient Facility
  2. IceCube-200512A: IceCube observation of a high-energy neutrino candidate event
  3. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  4. FRB/X-ray bursts from SGR 1935+2154: No Neutrino Counterpart in ANTARES data
  5. Swift Detection of a burst from SGR Swift J1818.0-1607
  6. SGR 1935+2154 the Insight-HXMT observation plan
  7. Fermi GBM observation of a bright flare from magnetar SGR 1935+2154
  8. IceCube-200425A: No significant detection in HAWC
  9. IceCube-200425A: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-200425A: Upper limits from Fermi-GBM Observations
  11. Gagarin-day GRB 200412B: observations with the 3.6m Devasthal Optical Telescope
  12. IceCube-200425A - IceCube observation of a high-energy neutrino candidate event
  13. GRB 200425A: Swift detection of a burst
  14. GRB 200424A: Swift ToO observations
  15. IceCube-200421A: Upper limits from a search for additional neutrino events in IceCube
  16. bright SGR burst detected by CALET Gamma-Ray Burst Monitor
  17. IceCube-200421A: No Neutrino Counterpart in ANTARES data
  18. IceCube-200421A: No significant detection in HAWC
  19. IceCube-200421A: not observable by Fermi-GBM
  20. IceCube-200421A - IceCube observation of a high-energy neutrino candidate event
  21. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  22. Konus-Wind observation of GRB 200415A (a magnetar Giant Flare in Sculptor Galaxy?)
  23. GRB 200416A: Swift detection of a burst with an optical afterglow
  24. IceCube-200410A: No significant detection in HAWC
  25. GRB 200412B: Fermi GBM detection
  26. IceCube-200410A: Upper limits from a search for additional neutrino events in IceCube
  27. GRB 200412B: Tiled Swift observations
  28. IceCube-200410A: Upper limits from Fermi-GBM Observations
  29. IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
  30. GRB 200409A: No detection of radio emission 5 hours post-burst
  31. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  32. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  33. Fermi GBM Sub-Threshold Detection of GRB 200409A
  34. GRB 200409A: Swift detection of a burst with an optical counterpart
  35. GRB 200405B: Swift ToO observations
  36. GRB 200325B: Swift-XRT and UVOT observations
  37. GRB 200325B: Mondy, CrAO, AbAO afterglow confirmation and refined photometry of MASTER OT J111012.51+274912.8
  38. GRB 200325B: Swift ToO observations
  39. GRB 200325B: MASTERt OT detection
  40. GRB 200324A: Swift detection of a burst
  41. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  42. LIGO/Virgo S200316bj: Updated Sky Localization and EM Bright Classification
  43. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  44. LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
  45. LIGO/Virgo S200316bj: Upper limits from Fermi-GBM Observations
  46. LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
  47. LIGO/Virgo S200316bj: Upper limits from IceCube neutrino searches
  48. LIGO/Virgo S200316bj: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo S200311bg: Updated Sky Localization and EM Bright Classification
  50. Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
  51. LIGO/Virgo S200311bg: Not observable by CALET
  52. LIGO/Virgo S200224ca: DESGW Summary of DECam Observations
  53. LIGO/Virgo S200311bg: Upper limits from IceCube neutrino searches
  54. LIGO/Virgo S200311bg: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo S200308e: Retraction of GW compact binary merger candidate
  56. LIGO/Virgo S200302c: No notable candidates in GOTO imaging
  57. GRB 200306C: Swift detection of a burst with an optical counterpart
  58. LIGO/Virgo S200225q: No notable candidates in GOTO imaging
  59. GRB 200303A: NOT optical observations
  60. LIGO/Virgo S200303ba: Retraction of GW compact binary merger candidate
  61. GRB 200303A: GOTO observations upper limit
  62. GRB 200303A: Swift detection of a burst
  63. LIGO/Virgo S200302c: Updated Sky Localization
  64. LIGO/Virgo S200302c: No counterpart candidates in HAWC observations
  65. LIGO/Virgo S200302c: Upper limits from Fermi-GBM Observations
  66. LIGO/Virgo S200302c : no neutrino counterpart candidate in ANTARES search
  67. LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
  68. LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
  69. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  70. IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
  71. GRB 200228B: KAIT Optical Upper Limit
  72. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
  73. IceCube-200227A : Upper limits from Insight-HXMT/HE observations
  74. HAWC-200216A: No Neutrino Counterpart in ANTARES Search
  75. IceCube-200227A: Upper limits from Fermi-GBM Observations
  76. IceCube-200227A: IceCube observation of a high-energy neutrino candidate event
  77. GRB 200227A: Swift detection of a burst
  78. LIGO/Virgo S200225q: Not observable by CALET
  79. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  80. LIGO/Virgo S200225q: Updated Sky Localization
  81. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  82. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  83. GRB 200219A: Chandra rapid ToO upper limit
  84. LIGO/Virgo S200219ac: Updated Sky Localization
  85. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  86. LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
  87. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  88. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  89. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  90. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  91. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  92. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  93. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  94. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  95. GRB 200219C: Swift-XRT afterglow confirmation
  96. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  97. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  98. GRB 200219C: Mondy and TSHAO optical observations
  99. GRB 200219C: DDOTI Observations
  100. GRB 200219C: Tiled Swift observations

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