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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"

8518 results found.

  1. IceCube-200530A: not observable by Fermi-GBM
  2. IceCube-200530A: No significant detection in HAWC
  3. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  4. IceCube-200530A: No ANTARES neutrino counterpart
  5. IceCube-200530A - IceCube observation of a high-energy neutrino candidate event
  6. GRB 200529A: Swift detection of a burst
  7. GRB 200528A: Swift detection of a burst
  8. IceCube-200523A: Upper limits from a search for additional neutrino events in IceCube
  9. GRB 200522A: HST F125W new point source detection
  10. GRB 200522A: Hubble Space Telescope Near-IR F160W Observations
  11. GRB 200524A: Correction to the GCN 27800
  12. GRB 200524A: 3.6m DOT observations of the afterglow candidate ZTF20abbiixp
  13. GRB 200524A: GROWTH-India confirmation of optical afterglow
  14. GRB 200524A: Swift ToO observations
  15. IceCube-200523A: Upper limits from Fermi-GBM Observations
  16. IceCube-200523A - IceCube observation of a high-energy neutrino candidate event
  17. GRB 200522A: Coincident catalogued galaxy at z~0.4
  18. GRB 200517A: Swift-XRT Confirmation of afterglow
  19. GRB 200519A: R-band follow-up from HCT
  20. GRB 200519A: LCO Optical Afterglow Detection
  21. Fermi GBM Sub-Threshold Detection of GRB 200517A
  22. GRB 200519A: Swift detection of a burst with an optical afterglow
  23. GRB 200517A: Tiled Swift observations
  24. Swift Detection of a burst from SGR Swift J1818.0-1607
  25. GRB 200514B: GROWTH-India follow-up of ZTF20aazpphd (AT2020jww)
  26. IceCube-200512A: Upper limits from a search for additional neutrino events in IceCube
  27. Fermi GBM Sub-Threshold Detection of GRB 200512A
  28. GRB 200512A: Swift detection of a burst
  29. IceCube-200512A: No Candidate Counterparts from the Zwicky Transient Facility
  30. IceCube-200512A: IceCube observation of a high-energy neutrino candidate event
  31. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  32. FRB/X-ray bursts from SGR 1935+2154: No Neutrino Counterpart in ANTARES data
  33. Swift Detection of a burst from SGR Swift J1818.0-1607
  34. SGR 1935+2154 the Insight-HXMT observation plan
  35. Fermi GBM observation of a bright flare from magnetar SGR 1935+2154
  36. IceCube-200425A: No significant detection in HAWC
  37. IceCube-200425A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-200425A: Upper limits from Fermi-GBM Observations
  39. Gagarin-day GRB 200412B: observations with the 3.6m Devasthal Optical Telescope
  40. IceCube-200425A - IceCube observation of a high-energy neutrino candidate event
  41. GRB 200425A: Swift detection of a burst
  42. GRB 200424A: Swift ToO observations
  43. IceCube-200421A: Upper limits from a search for additional neutrino events in IceCube
  44. bright SGR burst detected by CALET Gamma-Ray Burst Monitor
  45. IceCube-200421A: No Neutrino Counterpart in ANTARES data
  46. IceCube-200421A: No significant detection in HAWC
  47. IceCube-200421A: not observable by Fermi-GBM
  48. IceCube-200421A - IceCube observation of a high-energy neutrino candidate event
  49. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  50. Konus-Wind observation of GRB 200415A (a magnetar Giant Flare in Sculptor Galaxy?)
  51. GRB 200416A: Swift detection of a burst with an optical afterglow
  52. IceCube-200410A: No significant detection in HAWC
  53. GRB 200412B: Fermi GBM detection
  54. IceCube-200410A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 200412B: Tiled Swift observations
  56. IceCube-200410A: Upper limits from Fermi-GBM Observations
  57. IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
  58. GRB 200409A: No detection of radio emission 5 hours post-burst
  59. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  60. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  61. Fermi GBM Sub-Threshold Detection of GRB 200409A
  62. GRB 200409A: Swift detection of a burst with an optical counterpart
  63. GRB 200405B: Swift ToO observations
  64. GRB 200325B: Swift-XRT and UVOT observations
  65. GRB 200325B: Mondy, CrAO, AbAO afterglow confirmation and refined photometry of MASTER OT J111012.51+274912.8
  66. GRB 200325B: Swift ToO observations
  67. GRB 200325B: MASTERt OT detection
  68. GRB 200324A: Swift detection of a burst
  69. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  70. LIGO/Virgo S200316bj: Updated Sky Localization and EM Bright Classification
  71. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  72. LIGO/Virgo S200316bj: upper limits from AGILE/GRID observations
  73. LIGO/Virgo S200316bj: Upper limits from Fermi-GBM Observations
  74. LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
  75. LIGO/Virgo S200316bj: Upper limits from IceCube neutrino searches
  76. LIGO/Virgo S200316bj: Identification of a GW compact binary merger candidate
  77. LIGO/Virgo S200311bg: Updated Sky Localization and EM Bright Classification
  78. Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
  79. LIGO/Virgo S200311bg: Not observable by CALET
  80. LIGO/Virgo S200224ca: DESGW Summary of DECam Observations
  81. LIGO/Virgo S200311bg: Upper limits from IceCube neutrino searches
  82. LIGO/Virgo S200311bg: Identification of a GW compact binary merger candidate
  83. LIGO/Virgo S200308e: Retraction of GW compact binary merger candidate
  84. LIGO/Virgo S200302c: No notable candidates in GOTO imaging
  85. GRB 200306C: Swift detection of a burst with an optical counterpart
  86. LIGO/Virgo S200225q: No notable candidates in GOTO imaging
  87. GRB 200303A: NOT optical observations
  88. LIGO/Virgo S200303ba: Retraction of GW compact binary merger candidate
  89. GRB 200303A: GOTO observations upper limit
  90. GRB 200303A: Swift detection of a burst
  91. LIGO/Virgo S200302c: Updated Sky Localization
  92. LIGO/Virgo S200302c: No counterpart candidates in HAWC observations
  93. LIGO/Virgo S200302c: Upper limits from Fermi-GBM Observations
  94. LIGO/Virgo S200302c : no neutrino counterpart candidate in ANTARES search
  95. LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
  96. LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
  97. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  98. IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 200228B: KAIT Optical Upper Limit
  100. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification

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