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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"

19722 results found.

  1. GRB 240523A: Enhanced Swift-XRT position
  2. GRB 240523A: Swift detection of a burst
  3. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  4. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  5. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  6. GRB 240504A: VZLUSAT-2 detection
  7. GRB 240516A: Swift/UVOT Upper Limits
  8. GRB 240519A: AstroSat CZTI detection
  9. EP240518a: possibly identified with a flare star by EP-FXT
  10. EP240518a: EP-WXT detection of a new X-ray transient
  11. Fermi GRB 240517A: Global MASTER-Net observations report
  12. IPN triangulation of GRB 240514B (short)
  13. GRB 240513A: Swift ToO observations
  14. GRB 240511A: Observations from GTC/OSIRIS+
  15. GRB 240516A: Swift detection of a burst
  16. GRB 240511A: radio detection of afterglow candidate
  17. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  18. LIGO/Virgo/KAGRA S240422ed: Las Cumbres Observatory Follow-up Observations of the Localization Region
  19. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  20. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  22. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  23. GRB 240513A: Tiled Swift observations
  24. LAT GRB240513.31: Global MASTER-Net observations report
  25. GRB 240511A: J-band observations with WINTER
  26. GRB 240511A: Enhanced Swift-XRT position
  27. GRB 240511A : MITSuME Akeno optical upper limits
  28. GRB 240511A: Swift-XRT refined Analysis
  29. GRB 240511A: Swift detection of a burst
  30. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  31. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  32. EP240506a: Xinglong optical upper limit
  33. EP240506a: Archival radio searching
  34. EP240506a: TRT optical upper limit
  35. EP240506a: Optical upper limit with Kinder observations
  36. IPN triangulation of GRB 240504A
  37. GRB 240502A: 1.3m DFOT Optical upper limit
  38. EP240506a: EP-WXT detection of a new fast X-ray transient
  39. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  40. GW170817: VLA observations at ~5.5 yrs since merger
  41. GRB 240415A 1.3m DFOT Optical upper limit
  42. Fermi GRB 240502B: Global MASTER-Net observations report
  43. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  44. X-ray transient EP240414a: Detection of associated supernova
  45. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  46. Fermi-LAT gamma-ray observations of IceCube-240424A
  47. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  48. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  49. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
  50. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  51. EP240426b: AST3-2 optical upper limit
  52. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  53. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  54. EP240426b: EP-WXT detection of a new fast X-ray transient
  55. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
  56. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  57. XMM-Newton observation of EP240426a
  58. GRB 240414A: NOEMA detection
  59. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  60. EP240426a: GMG optical upper limit
  61. LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations
  62. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  63. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  64. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  65. GRB 240422A: Glowbug gamma-ray detection
  66. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  67. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  68. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  69. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  70. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  71. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  72. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a
  73. LIGO/Virgo/KAGRA S240422ed: Archival DECaPSs2 observations of the field of Mag24a
  74. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  75. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  76. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  77. LIGO/Virgo/KAGRA S240422ed: LAST optical observations
  78. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  79. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  80. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  81. LXT240402A/GRB240402B: Chandra X-ray detection
  82. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  83. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  84. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  85. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  86. GRB 240421A: Glowbug gamma-ray detection
  87. GRB 240414A: radio detection with the VLA
  88. Fermi-LAT gamma-ray observations of IceCube-240419A
  89. GRB 240414A: AMI-LA radio observations
  90. GRB 240414A: LBT optical detection
  91. GRB 240419B : MITSuME Akeno optical upper limits
  92. GRB 240421B: AstroSat CZTI detection
  93. GRB240421B: Zadko Observations
  94. GRB 240421B: Fermi GBM Observation
  95. GRB 240421B: J-band upper limits from WINTER
  96. GRB 240421B: Swift/UVOT Upper Limits
  97. GRB 240421B: Enhanced Swift-XRT position
  98. EP240417a: no counterpart detection by SOAR
  99. EP240420a: Xinglong decaying optical counterpart
  100. GRB 240421B: Swift detection of a burst

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