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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"

7447 results found.

  1. LIGO/Virgo S190512at: Updated sky localization
  2. LIGO/Virgo S190517h: ANTARES neutrino search
  3. LIGO/Virgo S190517h: Fermi GBM Observations
  4. LIGO/Virgo S190517h: HAWC follow-up
  5. LIGO-Virgo S190517h: AGILE GRID observations
  6. LIGO/Virgo S190517h: Identification of a GW compact binary merger candidate
  7. GRB 190515B: Swift detection of a burst
  8. LIGO/Virgo S190426c: AMI-LA radio observations of ZTF19aassfws
  9. LIGO/Virgo S190503bf: Gaia Photometric Alerts transient candidate
  10. LIGO/Virgo S190510g: Gaia Photometric Alerts transient candidate
  11. LIGO/Virgo S190510g: DECam-GROWTH optical counterpart candidate DG19qcso
  12. LIGO/Virgo S190513bm: ANTARES neutrino search
  13. LIGO/Virgo S190513bm: Fermi GBM Observations
  14. LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
  15. LIGO/Virgo S190513bm: HAWC follow-up
  16. LIGO/Virgo S190513bm: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo S190510g: Pan-STARRS and ATLAS observations and candidates
  18. LIGO/Virgo S190512at: ANTARES neutrino search
  19. LIGO/Virgo S190512at: Fermi GBM Observations
  20. LIGO/Virgo S190510g: Spectroscopic Classification of DECam-GROWTH and DES-GW Candidate DG19fqqk/desgw-190510c with Magellan
  21. LIGO/Virgo S190512at: Identification of a GW compact binary merger candidate
  22. IPN triangulation of GRB 190510A (short)
  23. LIGO/Virgo S190510g: KMTNet observation of DECam-GROWTH and DESGW candidates
  24. LIGO/Virgo S190510g: OT MASTER142812.05-013615.2 retraction as the kilonova candidate in GCN 24490
  25. LIGO/Virgo S190510g: MASTER OT detection inside low surface brightness galaxy
  26. LIGO/Virgo S190510g: Update on candidate significance
  27. LIGO/Virgo S190510g: DESGW counterpart candidates over 80% of the GW localization area
  28. LIGO/Virgo S190510g: DESGW counterpart candidate (desgw-190510a)
  29. LIGO/Virgo S190510g: Pierre Auger Observatory follow-up
  30. GRB 190511A: Swift detection of a burst
  31. LIGO/Virgo S190510g: SOAR/Goodman follow-up observations
  32. LIGO/Virgo S190510g: Optical Counterpart Candidates from DECam-GROWTH
  33. LIGO/Virgo S190510g: KMTNet observation
  34. LIGO/Virgo S190510g: CNEOST Follow-Up Observations
  35. LIGO/Virgo S190510g: Updated classification and data quality report
  36. LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
  37. LIGO/Virgo S190425z: CAHA-GRANDMA Observation of the Swift UVOT Source
  38. LIGO-Virgo S190426c: Pan-STARRS non-detection of ZTF19aassfws
  39. LIGO-Virgo S190510g: AGILE GRID observations
  40. LIGO/Virgo S190510g: CLU/NED Galaxies in the Localization Volume
  41. LIGO/Virgo S190510g: Updated localization from LIGO and Virgo data
  42. LIGO/Virgo S190510g: ANTARES neutrino search
  43. LIGO/Virgo S190510g: Identification of a GW compact binary merger candidate
  44. LIGO/Virgo S190510g: HAWC follow-up
  45. LIGO/Virgo S190426c: Archival VLASS Observations of ZTF19aassfws 14 days prior to Merger
  46. GRB 190507B: GOTO optical counterpart search
  47. LIGO/Virgo S190426c (BHNS candidate): Implications from Numerical Relativity
  48. IceCube-190504A: MASTER optical monitoring analysis
  49. LIGO/Virgo S190503bf: AstroSat CZTI upper limits
  50. LIGO/Virgo S190426c: Update on Source Classification
  51. Update to the Fermi GBM GCN Reporting
  52. IceCube-190504A: Swift-XRT Follow-up Observations
  53. IceCube-190503A: Swift-XRT Follow-up Observations
  54. LIGO/Virgo S190503bf: CALET Observations
  55. Search for counterpart to IceCube-190504A with ANTARES
  56. IceCube-190503A: Lick/KAIT Follow-Up Observations
  57. IPN triangulation of GRB 190504A (short)
  58. IceCube-190504A - IceCube observation of a high-energy neutrino candidate event
  59. LIGO/Virgo S190503bf: ANTARES neutrino search
  60. LIGO/Virgo S190503bf: Fermi-GBM Observations
  61. IceCube-190503A - IceCube observation of a high-energy neutrino candidate event
  62. LIGO/Virgo S190503bf: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo S190421ar: Updated localization and classification from LIGO and Virgo data
  64. GRB 190501A: Swift ToO observations
  65. LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidate
  66. LIGO/Virgo S190426c: Gaia Photometric Alerts transient candidate
  67. LIGO/Virgo S190426c: Swift rapid follow-up observations of S190425z and S190426c and URL for observation log for all future events
  68. LIGO/Virgo S190426c: GROWTH India follow-up of GRAWITA transient
  69. LIGO/Virgo S190426c: PS1 historical detections and ZTF photometry of Gaia19boq AT2019egk
  70. LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidate
  71. LIGO/Virgo S190426c: Gaia Photometric Alerts transient candidate
  72. LIGO/Virgo S190425z: DECam Observations of the UVOT Candidate Region
  73. LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
  74. LIGO/Virgo S190426c: Additional Candidates from the Zwicky Transient Facility
  75. LIGO/Virgo S190425z: No i-band detection of the Swift/UVOT transient in SkyMapper observations
  76. LIGO/Virgo S190425z: No source found at UVOT source location at 6 hrs after LVC report
  77. LIGO/Virgo S190426c: GROWTH India follow-up
  78. LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient in ASAS-SN observations hours before and after discovery
  79. LIGO/Virgo S190425z: Potential host galaxy of UVOT candidate counterpart found in BLISS
  80. LIGO/Virgo S190425z: Additional Candidates from the Zwicky Transient Facility
  81. LIGO/Virgo S190425z: ASAS-SN observations
  82. LIGO/Virgo S190425z: Pre-discovery NIR limits of the UVOT transient candidate from Gattini-IR
  83. LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
  84. LIGO/Virgo S190425z: GROWTH-India observations of the Swift/UVOT transient
  85. LIGO/Virgo S190425z: ZTF photometry of the UVOT transient candidate hours before discovery
  86. LIGO/Virgo S190426c: J-GEM optical/NIR follow-up observations
  87. LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search
  88. LIGO/Virgo S190426c: GOTO optical coverage - no notable counterparts
  89. LIGO/Virgo S190426c: Optical Wide-field Search with the Zwicky Transient Facility
  90. LIGO/Virgo S190426c: Updated localization from LIGO and Virgo data
  91. LIGO/Virgo S190426c: CALET Observations
  92. LIGO/Virgo S190425z: Lulin Observations of Counterpart Search
  93. ANTARES follow-up of the GW candidate S190426c
  94. LIGO/Virgo S190425z - ePESSTO+ spectrum of candidate PS19qu
  95. LIGO/Virgo S190425z: ANU 2.3m early observations of ZTF19aarykkb
  96. LIGO/Virgo S190426c: GROWTH India follow-up
  97. LIGO/Virgo S190426c: STARE2 simultaneous L-band radio observations
  98. LIGO/Virgo S190426c: a possible lensed NS-NS merger
  99. LIGO/Virgo S190426c: Tentative Red Transient Candidate from Las Cumbres Observatory
  100. LIGO/Virgo S190426c: Fermi GBM Observations

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