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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. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  2. GRB 200224B: DDOTI/OAN optical observations report
  3. LIGO/Virgo S200219ac: Updated Sky Localization
  4. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  5. LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
  6. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  7. IPN triangulation of GRB 200221A (short)
  8. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  9. Fermi trigger No 604231129: Global MASTER-Net observations report
  10. LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
  11. LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
  12. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  13. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  14. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  15. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  16. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  17. LIGO/Virgo S200225q: Global MASTER-Net observations report
  18. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  19. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  20. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  21. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  22. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  23. GRB 200224A: Swift-BAT refined analysis
  24. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  25. LIGO/Virgo S200224ca: not observable by Fermi-GBM
  26. GRB 200224A: LCO Upper Limits
  27. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  28. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  29. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  30. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  31. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  32. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  33. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  34. IPN triangulation of GRB 200224C
  35. GRB 200224A: Swift/UVOT Detection
  36. Correction in name: GRB 200224B and GRB 200224C (not GRB 200224A)
  37. GRB 200219C: Swift-XRT afterglow confirmation
  38. GRB 200224A: Swift-XRT refined Analysis
  39. GRB 200224C: Fermi GBM Final Real-time Localization
  40. GRB 200224A: Tautenburg observations
  41. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  42. Fermi trigger No 604213554: Global MASTER-Net observations report
  43. GRB 200224B: Fermi GBM Final Real-time Localization
  44. GRB 200224A: Swift detection of a burst
  45. Swift GRB200224.14: Global MASTER-Net observations report
  46. GRB 200223A: Fermi GBM Final Real-time Localization
  47. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  48. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  49. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  50. IPN triangulation of GRB 200219B (inconsistent with the LIGO/Virgo S200219ac)
  51. GRB 200219C: OAJ afterglow confirmation
  52. GRB 200219A: UVOT Upper Limits
  53. GRB 200219A: FRAM-Auger optical limit
  54. GRB 200219C: CALET Gamma-Ray Burst Monitor detection
  55. GRB 200219C: Mondy and TSHAO optical observations
  56. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  57. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  58. GRB 200221A: Fermi GBM Final Real-time Localization
  59. Fermi trigger No 603949983: Global MASTER-Net observations report
  60. GRB 200219C: Swift-XRT afterglow detection
  61. GRB 200219C: DDOTI Observations
  62. GRB 200219C: Fermi GBM detection
  63. LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
  64. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  65. GRB 200219C: Tiled Swift observations
  66. GRB 200219C: Fermi-LAT detection
  67. GRB 200215A: LCO Optical Upper Limits
  68. LIGO/Virgo S200219ac: No transient candidates in CALET observations
  69. GRB 200219A, Swift-BAT refined analysis
  70. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  71. Fermi trigger No 603849435: Global MASTER-Net observations report
  72. GRB 200219C: Fermi GBM Final Real-time Localization
  73. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  74. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  75. GRB 200219A: Swift-XRT refined Analysis correction
  76. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  77. LIGO/Virgo S200213t: Keck/LRIS spectroscopy of counterpart candidates from the Zwicky Transient Facility
  78. GRB 200219A: Swift-XRT refined Analysis
  79. GRB 200219A: Enhanced Swift-XRT position
  80. GRB 200219A: Fermi GBM observation
  81. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  82. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  83. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  84. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  85. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  86. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  87. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo S200219ac: Global MASTER-Net observations report
  89. GRB 200216B: second epoch optical upper limit at Mondy observatory
  90. GRB 200219B: Fermi GBM Final Real-time Localization
  91. GRB 200219A: MASTER catalog automatic possible Host Galaxy candidate
  92. GRB 200219A: Swift detection of a short burst
  93. Swift GRB200219.32: Global MASTER-Net observations report
  94. GRB 200219A: Fermi GBM Final Real-time Localization
  95. GRB 200216B: Mondy and AbAO optical upper limits
  96. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  97. GRB 200216B: Swift-XRT refined Analysis
  98. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  99. LIGO/Virgo S200213t: APO Upper Limits for ZTF20aanakes/AT2020cly
  100. GRB 200216B: Swift-BAT refined analysis

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