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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"
  1. IceCube-200117A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  2. LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
  3. IceCube-200117A: IceCube observation of a high-energy neutrino candidate event
  4. GRB 200115A: AROMA-N Optical Observation
  5. GRB 200117A: Fermi GBM Final Real-time Localization
  6. IceCube Alert 200117.46: Global MASTER-Net observations report
  7. LIGO/Virgo S200115j: Swift-XRT sources
  8. LIGO/Virgo S200115j: Upper limits from CALET observations.
  9. LIGO/Virgo S200114f: ZTF Forced Photometry of the Swift Source S200114f_X2
  10. GRB 200111A: CALET Gamma-Ray Burst Monitor detection
  11. LIGO/Virgo S200115j: No notable candidates in GOTO imaging
  12. LIGO/Virgo S200114f: Upper Limits from Wide-Field Infrared Search with Palomar Gattini-IR
  13. GRB 200115A: DDOTI/OAN optical observations report
  14. LIGO/Virgo S200114f: Possible X-ray transient
  15. GRB 200115A: Mondy optical afterglow candidate
  16. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  17. LIGO/Virgo S200115j: No neutrino candidates at Pierre Auger Observatory
  18. LIGO/Virgo S200114f: Swift-XRT sources and observations
  19. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  20. LIGO/Virgo S200116ah: Retraction of GW compact binary merger candidate
  21. LIGO/Virgo S200116ah: Global MASTER-Net observations report
  22. GRB 200111A: AstroSat CZTI detection
  23. Baksan Neutrino Observatory Alert 200116.22: Global MASTER-Net observations report
  24. Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
  25. GRB 200115A: Swift-BAT refined analysis
  26. LIGO/Virgo S200115j: no counterpart candidates in the Swift/BAT observations
  27. IPN triangulation of GRB 200111A
  28. LIGO/Virgo S200115j High Rank XRT sources are spurious
  29. GRB 200115A: MITSuME Okayama optical upper limits
  30. LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
  31. LIGO/Virgo S200115j: Upper limits from Fermi-GBM Observations
  32. GRB 200114A: Insight-HXMT/HE detection
  33. GRB 200115A: Nanshan-0.6m optical upper limit
  34. GRB 200115A: Swift detection of a burst
  35. Swift GRB200115.49: Global MASTER-Net observations report
  36. LIGO/Virgo S200115j: upper limits from AGILE/GRID observations
  37. LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
  38. LIGO/Virgo S200115j: Candidates from the Zwicky Transient Facility
  39. LIGO/Virgo S200115j: INTEGRAL was inactive at the time of the event
  40. LIGO/Virgo S200115j: upper limits from AGILE/MCAL observations
  41. LIGO/Virgo S200114f: AT2020vr, AT2020vt, AT2020wa and AT2020wc 10.4m GTC spectroscopy
  42. LIGO/Virgo S200115j: Revised list of possible host galaxies with the new skymap
  43. LIGO/Virgo S200115j : no neutrino counterpart candidate in ANTARES search
  44. LIGO/Virgo S200114f: Upper limits from CALET observations.
  45. LIGO/Virgo S200115j: Coverage and upper limits from MAXI/GSC observations
  46. LIGO/Virgo S200115j: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo S200115j: No counterpart candidates in HAWC observations
  48. LIGO/Virgo S200115j: Upper limits from IceCube neutrino searches
  49. LIGO/Virgo trigger S200115j: Possible host galaxies
  50. LIGO/Virgo S200115j: Global MASTER-Net observations report
  51. GRB 200114A: DDOTI/OAN optical observations report
  52. LIGO/Virgo S200114f: Candidates from SAGUARO observations
  53. LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
  54. LIGO/Virgo S200114f: Constraints on a CCSN origin from KM3NeT MeV neutrino search.
  55. LIGO/Virgo S200114f: SAGUARO previous detection of ZTF candidate ZTF20aafeaqk (AT2020vx)
  56. LIGO/Virgo S200114f: upper limits from AGILE-GRID observations
  57. LIGO/Virgo S200114f: no counterpart candidates in the Swift/BAT observations
  58. IceCube-200109A: Candidate Counterparts from the Zwicky Transient Facility
  59. GRB 200114A: AstroSat CZTI detection
  60. LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations
  61. LIGO/Virgo S200114f: not observable by AGILE at the event time
  62. LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  63. LIGO/Virgo S200114f : no neutrino counterpart candidate in ANTARES search
  64. LIGO/Virgo S200114f: Candidates from the Zwicky Transient Facility
  65. LIGO/Virgo S200112r: Upper limits from CALET observations
  66. LIGO/Virgo S200114f: Upper limits from Fermi-GBM Observations
  67. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  68. Fermi trigger No 600666048: Global MASTER-Net observations report
  69. GRB 200114A: BALROG localization (Fermi Trigger 600666048 / GRB 200114153)
  70. GRB 200114A: Fermi GBM Final Real-time Localization
  71. LIGO/Virgo S200114f: Identification of a GW unmodeled transient candidate
  72. LIGO/Virgo S200114f: No counterpart candidates in HAWC observations
  73. LIGO/Virgo S200114f: Upper limits from IceCube neutrino searches
  74. LIGO/Virgo S200114f: Global MASTER-Net observations report
  75. LIGO/Virgo S200112r: Upper limits from Insight-HXMT/HE observations
  76. GRB 200112A: AstroSat CZTI detection
  77. Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034
  78. LIGO/Virgo 200112r: No counterpart candidates in Fermi-LAT observations
  79. LIGO/Virgo S200112r: not observable by Fermi-GBM
  80. LIGO/Virgo S200112r: not observable by Fermi-GBM
  81. LIGO/Virgo S200112r: upper limits from AGILE/GRID observations
  82. LIGO/Virgo S200112r: Swift/BAT in the South Atlantic Anomaly
  83. LIGO/Virgo S200112r: upper limits from AGILE/MCAL observations
  84. LIGO/Virgo S200112r: INTEGRAL was inactive at the time of the event
  85. LIGO/Virgo S200112r: Coverage and upper limits from MAXI/GSC observations
  86. LIGO/Virgo S200112r: No counterpart candidates in HAWC observations
  87. LIGO/Virgo S200112r : no neutrino counterpart candidate in ANTARES search
  88. LIGO/Virgo S200112r: Global MASTER-Net observations report
  89. LIGO/Virgo S200112r: Upper limits from IceCube neutrino searches
  90. LIGO/Virgo S200112r: Identification of a GW compact binary merger candidate
  91. GRB 200111A: Insight-HXMT/HE detection
  92. GRB 200112A: BALROG localization (Fermi Trigger 600525396 / GRB 200112525)
  93. Fermi trigger No 600525396: Global MASTER-Net observations report
  94. GRB 200112A: Fermi GBM Final Real-time Localization
  95. GRB 200109A: Insight-HXMT/HE detection
  96. IceCube 200109A: No significant detection in HAWC
  97. Fermi-LAT ANTARES coincidence: No significant detection in HAWC
  98. IceCube-200109A: Upper limits from a search for additional neutrino events in IceCube
  99. Fermi trigger No 600448273: Global MASTER-Net observations report
  100. GRB 200111A: Fermi GBM Final Real-time Localization

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