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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"

8293 results found.

  1. IceCube-200806A: Upper limits from Fermi-GBM Observations
  2. GRB 200806A: Swift detection of a burst
  3. IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
  4. GRB 200803A: Fermi GBM detection
  5. GRB 200803A: Tiled Swift observations
  6. AX J1846.4-0258: Swift-BAT refined analysis
  7. Konus-Wind detection of GRB 200729A
  8. Swift Detection of an SGR-like flare from AX J1846.4-0258
  9. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  10. GRB 200729A: IceCube neutrino search
  11. GRB 200729A: Spitzer archival source detection
  12. GRB 200729A: NOT optical upper limits
  13. GRB 200729A: Swift detection of a burst
  14. GRB 200723A: ATLAS observations of GOTO candidate AT2020qer
  15. GRB 200723A: Swift ToO observations
  16. GRB 200723A: GOTO candidate afterglow and host galaxy
  17. AMON IC_HAWC 170720: No Neutrino Counterpart detected with ANTARES
  18. GRB 200716C: Optical observations from HCT
  19. GRB 200522A: HST NIR counterpart confirmation
  20. GRB 200716C: Swift detection of a burst with an optical counterpart
  21. GRB 200715A: Swift ToO observations
  22. GRB 200714E: Swift ToO observations
  23. GRB 200522A: Candidate Optical/nIR Counterpart from Gemini and HST Imaging
  24. GRB 200713A: Swift detection of a burst
  25. GRB 200711A: KAIT Optical Upper Limit
  26. GRB 200711A: Swift detection of a burst
  27. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  28. HAWC-200907A: No Neutrino Counterpart detected with ANTARES
  29. GRB 200709B: Tiled Swift observations
  30. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  31. Fermi-GBM Sub-Threshold Detection of GRB 200701A
  32. GRB 200630A: Swift detection of a burst
  33. GRB 200623A: Further MMTCam Observations of XRT Source #3
  34. GRB 200623A: LBT optical observations
  35. GRB 200625A: Swift ToO observations
  36. GRB 200623A: Swift/UVOT Upper Limits
  37. GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
  38. GRB 200623A: TNG optical observations
  39. GRB 200623A: AbAO afterglow candidate within XRT #2
  40. GRB 200623A: Swift ToO observations
  41. IceCube-200620A: No significant detection in HAWC
  42. IceCube-200620A: Upper limits from a search for additional neutrino events in IceCube
  43. IceCube-200620A: MASTER previous detection of ZTF20abgvabi/AT2020ncr
  44. IceCube-200620A: not observable by Fermi-GBM
  45. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  46. IceCube-200620A: No ANTARES neutrino counterpart
  47. IceCube-200620A - IceCube observation of a high-energy neutrino candidate track-like event
  48. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  49. LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
  50. LIGO/Virgo MS200618bx: Retraction of a test binary neutron star candidate
  51. LIGO/Virgo MS200618bq: Retraction of a test binary neutron star candidate
  52. IceCube-200530A - SN2020lls likely unrelated
  53. LIGO/Virgo MS200614ct: Identification of a test binary black hole candidate
  54. IceCube-200615A: No significant detection in HAWC
  55. IceCube-200614A: No significant detection in HAWC
  56. IceCube-200615A: Upper limits from a search for additional neutrino events in IceCube
  57. Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
  58. LIGO/Virgo MS200615ce: Identification of a test binary black hole candidate
  59. LIGO/Virgo MS200614bz: Test Identification of a binary neutron star candidate
  60. IceCube-200615A: Upper limits from Fermi-GBM Observations
  61. IceCube-200614A: Upper limits from a search for additional neutrino events in IceCube
  62. IceCube-200614A: not observable by Fermi-GBM
  63. LIGO/Virgo MS200615h: Retraction of a test binary neutron star candidate
  64. IceCube-200615A: IceCube observation of a high-energy neutrino candidate event
  65. IceCube-200614A - IceCube observation of a high-energy neutrino candidate track-like event
  66. GRB 200613A: Kitab and AbAO optical afterglow observations, host galaxy candidate
  67. GRB 200613A: Candidate afterglow from OAJ
  68. GRB 200613A: Swift ToO observations
  69. GRB 200612A: Swift detection of a burst
  70. IceCube-200530A - SN2020lam classified as SN II without evidence of CSM interaction
  71. GRB 200522A: Further HST F125W Observations
  72. Correction to the GCN 27886: Previous bursts of 1RXS J1708-4009 (Swift trigger 975998)
  73. 1RXS J1708−4009: Swift-BAT refined analysis
  74. Swift detection of an SGR-like burst from 1RXS J1708−4009
  75. IceCube-200530A: Upper limits from a search for additional neutrino events in IceCube
  76. IceCube-200530A: not observable by Fermi-GBM
  77. IceCube-200530A: No significant detection in HAWC
  78. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  79. IceCube-200530A: No ANTARES neutrino counterpart
  80. IceCube-200530A - IceCube observation of a high-energy neutrino candidate event
  81. GRB 200529A: Swift detection of a burst
  82. GRB 200528A: Swift detection of a burst
  83. IceCube-200523A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 200522A: HST F125W new point source detection
  85. GRB 200522A: Hubble Space Telescope Near-IR F160W Observations
  86. GRB 200524A: Correction to the GCN 27800
  87. GRB 200524A: 3.6m DOT observations of the afterglow candidate ZTF20abbiixp
  88. GRB 200524A: GROWTH-India confirmation of optical afterglow
  89. GRB 200524A: Swift ToO observations
  90. IceCube-200523A: Upper limits from Fermi-GBM Observations
  91. IceCube-200523A - IceCube observation of a high-energy neutrino candidate event
  92. GRB 200522A: Coincident catalogued galaxy at z~0.4
  93. GRB 200517A: Swift-XRT Confirmation of afterglow
  94. GRB 200519A: R-band follow-up from HCT
  95. GRB 200519A: LCO Optical Afterglow Detection
  96. Fermi GBM Sub-Threshold Detection of GRB 200517A
  97. GRB 200519A: Swift detection of a burst with an optical afterglow
  98. GRB 200517A: Tiled Swift observations
  99. Swift Detection of a burst from SGR Swift J1818.0-1607
  100. GRB 200514B: GROWTH-India follow-up of ZTF20aazpphd (AT2020jww)

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