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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 190419A: AstroSat CZTI detection
  2. LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search
  3. LIGO/Virgo S190425z: Further confirmation for the classification of PS19qp/AT 2019ebq as a supernova
  4. Fermi GRB190427.19 Global MASTER-Net observations report
  5. GRB 190427A: Fermi GBM detection
  6. LIGO/Virgo S190426c: MMT Follow-Up Observations
  7. LIGO/Virgo S190426c: GOTO optical coverage - no notable counterparts
  8. GRB 190427A: Lick/Nickel telescope optical observations
  9. LIGO/Virgo S190426c: Lick/KAIT Follow-Up Observations
  10. GRB 190427A: MITSuME Akeno optical upper limits
  11. GRB 190427A: COATLI Optical Observations
  12. LIGO/Virgo S190426c: CNEOST Optical Observations
  13. LIGO/Virgo S190425z: CNEOST Optical Observations
  14. LIGO/Virgo S190426c: Infrared Wide-field Search with Palomar Gattini-IR
  15. LIGO/Virgo S190426c: Optical Wide-field Search with the Zwicky Transient Facility
  16. GRB 190427A: RATIR Optical and NIR Observations
  17. LIGO/Virgo S190426c: Nanshan/NEXT Observation of Galaxies
  18. LIGO/Virgo S190426c: Insight-HXMT/HE observation
  19. LIGO/Virgo S190426c: Updated localization to fix data format issue
  20. LIGO/Virgo S190426c: Hobby-Eberly Telescope VIRUS observations of target galaxies.
  21. LIGO/Virgo S190426c: Updated localization from LIGO and Virgo data
  22. LIGO/Virgo S190426c: CALET Observations
  23. LIGO/Virgo S190426c: Imaging confirmation and host spectroscopy of DG19vkgf
  24. LIGO/Virgo S190425z: Lulin Observations of Counterpart Search
  25. LIGO/Virgo S190426c: Swift-XRT sources
  26. GRB 190427A: BOOTES-1 and BOOTES-5/JGT early follow-up observations
  27. ANTARES follow-up of the GW candidate S190426c
  28. LIGO/Virgo S190425z: BOOTES-5/JGT observations of galaxies
  29. LIGO/Virgo S190425z - ePESSTO+ spectrum of candidate PS19qu
  30. LIGO/Virgo S190426c: Red and blue transients identified with DECam
  31. LIGO/Virgo S190425z: Lijiang 2.4-m Telescope Follow-up Observations
  32. LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
  33. GRB 190427A: NOT optical observations
  34. GRB 190427A: Swift-XRT observations
  35. Swift GRB190427.19 Global MASTER-Net observations report
  36. LIGO/Virgo S190425z: Additional Pan-STARRS transients in the skymap
  37. GRB 190427A: Swift detection of a short burst
  38. LIGO/Virgo S190425z: ANU 2.3m early observations of ZTF19aarykkb
  39. LIGO/Virgo S190426c: MAXI/GSC Observations
  40. LIGO/Virgo S190426c: GROWTH India follow-up
  41. LIGO/Virgo S190426c: Public DECam Observations
  42. LIGO/Virgo S190425z: GRANDMA follow-up observations with Les Makes-T60, AZT-8 and Abastumani-T70
  43. LIGO/Virgo S190426c: Swift/BAT Counterpart Search
  44. LIGO/Virgo S190426c: STARE2 simultaneous L-band radio observations
  45. SUBJECT: LIGO/Virgo S190425z: GRAWITA LBT spectroscopic observations
  46. LIGO/Virgo S190426c: Nemo is Unrelated
  47. LIGO/Virgo S190426c: a possible lensed NS-NS merger
  48. LIGO/Virgo S190426c: Tentative Red Transient Candidate from Las Cumbres Observatory
  49. LIGO/Virgo S190426c: Fermi GBM Observations
  50. LIGO/Virgo S190426c: SAO optical observation
  51. LIGO/Virgo S190426c: AGILE-GRID Observations
  52. LIGO-Virgo S190426c: AGILE MCAL observation
  53. LIGO/Virgo S190425z: Further MMT Follow-Up Observations
  54. LIGO/Virgo S190426c: Potential host galaxies from the GLADE catalog
  55. LIGO/Virgo S190426c: INTEGRAL prompt observation
  56. Baksan Neutrino Observatory Alert 190405.62: Global MASTER-Net:LIGO/Virgo S190425z: PanSTARR OT AT2019ebq/PS19qp
  57. LIGO/Virgo S190425z: Pierre Auger Observatory follow-up
  58. LIGO/Virgo S190425z: COATLI Observations of Galaxies
  59. LIGO/Virgo S190425z: RATIR Observations of Galaxies
  60. LIGO/Virgo S190426c: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo S190426c Global MASTER-Net observations report
  62. LIGO/Virgo S190426c: HAWC follow-up
  63. LIGO/Virgo S190425z: YAHPT Optical Observation
  64. LIGO/Virgo S190425z: Keck NIR spectroscopy shows AT2019ebq is a supernova
  65. LIGO/Virgo S190425z: Nearby Galaxies in the Updated Localization Volume
  66. LIGO/Virgo S190426c: IceCube Neutrino Search
  67. LIGO/Virgo S190425z: J-GEM spectroscopic observations of AT2019ebq/PS19qp with Subaru/FOCAS
  68. LIGO/Virgo S190425z: GROND observations of AT2019ebq/PS19qp
  69. LIGO/Virgo S190425z: Updated localization from LIGO and Virgo data
  70. LIGO/Virgo S190425z: TAROT-GRANDMA observation report
  71. LIGO/Virgo S190425z: AMI-LA radio observations of two ZTF afterglow candidates.
  72. LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  73. LIGO/Virgo S190425z: GOTO observations
  74. LIGO/Virgo S190425z: ZTF pre-merger limits on PS1 candidates
  75. LIGO/Virgo S190425z: LWA1 observations
  76. LIGO/Virgo GW190425z: GTC spectroscopic classification of AT2019ebq/PS19qp
  77. LIGO/Virgo S190425z: DCT ZTF19aarykkb spectroscopy
  78. LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometry of ZTF19aarykkb and ZTF19aarzaod
  79. LIGO/Virgo S190425z: CALET Observations
  80. LIGO/Virgo S190425z - ePESSTO+ spectrum of PS19qp shows red featureless source at z=0.037
  81. LIGO/Virgo S190425z: KMTNet Observation
  82. LIGO/Virgo S190425z - ePESSTO+ NTT spectrum of candidate PS19qo
  83. LIGO/Virgo S190425z: ZTF19aarzaod 1.5m OSN imaging and 10.4m GTC spectroscopy
  84. LIGO/Virgo S190425z: Insight-HXMT/HE observation
  85. LIGO/Virgo S190425z: Swope follow-up observations
  86. LIGO/Virgo S190425z - ePESSTO+ NTT observations
  87. LIGO/Virgo S190425z: Pan-STARRS observations and transients in the skymap
  88. LIGO/Virgo S190425z: ZTF19aarzaod WHT spectroscopy
  89. LIGO/Virgo S190425z: GRAWITA TNG observations of ZTF19aarzaod
  90. LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  91. LIGO/Virgo S190425z: ZTF19aarykkb Imaging from Las Cumbres Observatory
  92. LIGO/Virgo S190425z: SALT spectroscopy of ZTF19aarzaod as a likely type II supernova
  93. LIGO/Virgo S190425z: Liverpool Telescope spectroscopy of ZTF19aarykkb
  94. Problem with GCN Circular and status of the fix
  95. LIGO/Virgo S190425z: Liverpool Telescope non-detections of ATLAS candidates
  96. LIGO/Virgo S190425z - GROWTH-India follow-up of two ZTF candidates
  97. LIGO/Virgo S190425z - HCT spectroscopy
  98. LIGO/Virgo S190425z: STARE2 simultaneous L-band radio observations
  99. LIGO/Virgo S190425z: KPED Follow-Up Observations
  100. LIGO/Virgo S190425z: ATLAS observations of the S190425z skymap

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