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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').
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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"

4714 results found.

  1. LAT GRB240513.31: Global MASTER-Net observations report
  2. Fermi trigger No 737277727: Global MASTER-Net observations report
  3. Fermi trigger No 737247400: Global MASTER-Net observations report
  4. GRB 240511A : MITSuME Akeno optical upper limits
  5. LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate
  6. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  7. Fermi trigger No 736564880: Global MASTER-Net observations report
  8. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  9. GRB 240503A: AstroSat CZTI detection
  10. Fermi trigger No 736387941: Global MASTER-Net observations report
  11. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  12. Fermi trigger No 736379109: Global MASTER-Net observations report
  13. GRB 240502C: GOTO possible optical counterpart candidates
  14. Fermi GRB 240502B: Global MASTER-Net observations report
  15. Fermi GRB 240502A: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  17. Fermi GRB 240501A: Global MASTER-Net observations report
  18. Fermi trigger No 736197684: Global MASTER-Net observations report
  19. GRB 240408B: VZLUSAT-2 detection
  20. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  22. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  23. LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  25. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  26. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  27. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  28. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  29. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  30. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  31. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  32. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  33. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  34. IceCube Alert 240424.08: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  36. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  37. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  38. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  39. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  40. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  41. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  42. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  43. Fermi GRB 240422A: Global MASTER-Net observations report
  44. Fermi trigger No 735280430: Global MASTER-Net observations report
  45. Fermi trigger No 735089036: Global MASTER-Net observations report
  46. Fermi GRB 240417A: Global MASTER-Net observations report
  47. Improved IPN triangulation of GRB 240411A
  48. GRB 240415A: SAO RAS optical observations
  49. Fermi GRB 240415A: Global MASTER-Net observations report
  50. Fermi trigger No 734754044: Global MASTER-Net observations report
  51. IPN triangulation of GRB 240411A
  52. GRB 240414A : OHP/T193 redshift determination
  53. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  55. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  56. IceCube Alert 240412.23: Global MASTER-Net observations report
  57. GRB 240408B: GRBAlpha detection
  58. EP240408A: MASTER optical observations
  59. Swift Trigger 1220736: detection of 4U 1543-62.
  60. Fermi GRB 240408A: Global MASTER-Net observations report
  61. Fermi GRB 240407A: Global MASTER-Net observations report
  62. Fermi-LAT gamma-ray observations of IceCube-240327B
  63. Fermi-LAT gamma-ray observations of IceCube-240327A
  64. GRB 240331A: GRBAlpha detection
  65. GRB 240403B: Glowbug gamma-ray detection
  66. GRB 240403A: Glowbug gamma-ray detection
  67. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  68. GRB 240403A: Fermi GBM Detection
  69. LXT 240402A: MASTER optical observations with AGN in error-box
  70. GRB 240402B: GWAC-F50A optical upper limit
  71. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  72. Fermi trigger No 733808041: Global MASTER-Net observations report
  73. Fermi GRB 240402A: Global MASTER-Net observations report
  74. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  75. EP240331A: MASTER optical observations
  76. Transient EP240315a: J-band observations of AT2024eju with WIRC
  77. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  79. GRB 240329A: Glowbug gamma-ray detection
  80. GRB 240324A: AstroSat CZTI detection of a short burst
  81. GRB 240331A: AstroSat CZTI detection
  82. GRB 240329A: AstroSat CZTI detection
  83. GRB 240329A: GRBAlpha detection
  84. Fermi trigger No 733366352: Global MASTER-Net observations report
  85. Fermi GRB 240329A: Global MASTER-Net observations report
  86. Fermi GRB 240328B: Global MASTER-Net observations report
  87. Fermi GRB 240328A: Global MASTER-Net observations report
  88. X-ray transient EP240315a: continued ATCA monitoring
  89. IceCube-240327B: No candidates from the Zwicky Transient Facility
  90. GRB 240328C: Glowbug gamma-ray detection
  91. IceCube Alert 240327.68: Global MASTER-Net observations report
  92. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  93. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  94. Fermi trigger No 733097506: Global MASTER-Net observations report
  95. X-ray transient EP240315a: Ondrejov D50 optical limit
  96. Fermi trigger No 733092476: Global MASTER-Net observations report
  97. GRB 240320A: Glowbug gamma-ray detection
  98. Fermi trigger No 732937833: Global MASTER-Net observations report
  99. Fermi GRB 240320A: Global MASTER-Net observations report
  100. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection

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