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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').

10044 results found.

  1. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  2. EP240703a and EP240703b: Swift/XRT upper limits
  3. EP240703a: BTA observations
  4. EP240703c: EP-WXT detection of an X-ray transient
  5. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  6. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  7. EP240703b: EP-WXT detection of a fast X-ray transient
  8. EP240702a: Swift/XRT upper limit
  9. EP240703a: EP-WXT detection of a fast X-ray transient
  10. EP240702a: EP-WXT detection of a fast X-ray transient
  11. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  12. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  13. GRB 240615A: SAI CMO J- band observations
  14. EP240625a: GRANDMA Optical Upper Limits
  15. EP240626a: EP-FXT detection of the X-ray emission
  16. EP240626a: EP-WXT detection of a fast X-ray transient
  17. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  18. EP240625a: NOT optical counterpart candidate
  19. EP240625a: EP-FXT detection of the X-ray emission
  20. GRB 240624B: GRBAlpha detection
  21. EP240625a: EP-WXT detection of a fast X-ray transient
  22. GRB240624A: Fermi GBM Observation
  23. Swift GRB 240624A: Global MASTER-Net observations report
  24. GRB 240624A: Swift detection of a burst
  25. GRB 240619A: GRBAlpha detection
  26. EP240618a: Swift/XRT upper limit
  27. EP240617a: tentative Swift/XRT detection of the afterglow
  28. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  29. Fermi GBM Sub-Threshold Detection of GRB 240619C
  30. EP240618a: Abastumani optical observationsEP240618a
  31. EP240618a: GRANDMA Optical Upper Limits
  32. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  33. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  34. EP240617a: EP-WXT detection of a fast X-ray transient
  35. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  36. GRB 240615A: GOTO optical upper limits
  37. GRB 240603A: VZLUSAT-2 detection
  38. GRB 240612A: GRBAlpha detection
  39. GRB 240529A : MITSuME Akeno optical afterglow detection
  40. The EP-WXT source triggered on June 1st is likely a flaring star
  41. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  42. GRB 240529A : Mondy optical observations
  43. GRB 240529A: Redshift from GTC/OSIRIS+
  44. LXT 240528A: LEIA detection of a fast X-ray transient
  45. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  46. GRB 240523A: Swift detection of a burst
  47. Fermi GBM Sub-Threshold Detection of GRB 240516B
  48. GRB 240514B: VZLUSAT-2 detection
  49. GRB 240504A: VZLUSAT-2 detection
  50. GRB 240502A: VZLUSAT-2 detection
  51. GRB 240519A: GRBAlpha detection
  52. GRB 240516A: Swift/UVOT Upper Limits
  53. EP240518a: possibly identified with a flare star by EP-FXT
  54. EP240518a: EP-WXT detection of a new X-ray transient
  55. GRB 240514E: A possible candidate BD-21 1074
  56. GRB 240511A: Observations from GTC/OSIRIS+
  57. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  58. GRB 240514E: MAXI/GSC detection of a probable afterglow
  59. GRB 240514B: GRBAlpha detection
  60. GRB 240513A: Fermi-LAT detection
  61. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  62. GRB 240511A : MITSuME Akeno optical upper limits
  63. GRB 240511A: Swift detection of a burst
  64. EP240506a: CrAO ZTSH optical upper limit
  65. EP240506a: EP-WXT detection of a new fast X-ray transient
  66. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  67. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  68. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  69. GRB 240502C: GOTO possible optical counterpart candidates
  70. GRB 240501B: GRBAlpha detection
  71. GRB 240430A: GRBAlpha detection
  72. GRB 240426A: VZLUSAT-2 detection
  73. GRB 240425A: VZLUSAT-2 detection
  74. GRB 240408B: VZLUSAT-2 detection
  75. GRB 240407A: VZLUSAT-2 detection
  76. GRB 240425A: GRBAlpha detection
  77. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  78. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  79. EP240426b: EP-WXT detection of a new fast X-ray transient
  80. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  81. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  82. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  83. LVK S240422ed: Further Swift-XRT followup of three sources
  84. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  85. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
  86. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  87. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  88. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  89. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  90. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  91. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  92. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  93. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  94. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  95. GRB 240421B: GRBAlpha detection
  96. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  97. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  98. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  99. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  100. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation

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