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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').

9625 results found.

  1. EP240506a: CrAO ZTSH optical upper limit
  2. EP240506a: EP-WXT detection of a new fast X-ray transient
  3. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  4. Fermi trigger No 736564880: Global MASTER-Net observations report
  5. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  6. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  7. Fermi GRB 240504A: Global MASTER-Net observations report
  8. Fermi trigger No 736472503: Global MASTER-Net observations report
  9. GRB 240503A: AstroSat CZTI detection
  10. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  11. GRB 240502C: GOTO possible optical counterpart candidates
  12. GRB 240502A long GRB detected by INTEGRAL
  13. Fermi GRB 240501A: Global MASTER-Net observations report
  14. Fermi trigger No 736197684: Global MASTER-Net observations report
  15. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  16. GRB 240501B: AstroSat CZTI detection
  17. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  18. Fermi-LAT gamma-ray observations of IceCube-240424A
  19. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  20. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  21. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  22. EP240426b: EP-WXT detection of a new fast X-ray transient
  23. GRB 240426A: AstroSat CZTI detection
  24. XMM-Newton observation of EP240426a
  25. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  26. EP240426a: GMG optical upper limit
  27. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  28. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  29. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  30. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  31. GRB 240425A: Fermi GBM Final Real-time Localization
  32. Fermi trigger No 735697285: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  34. LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up
  35. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  36. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  37. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  38. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  39. IceCube Alert 240424.08: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  41. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  42. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  43. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  44. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  45. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  46. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  47. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  49. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  50. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  51. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  52. Fermi-LAT gamma-ray observations of IceCube-240419A
  53. GRB 240414A: AMI-LA radio observations
  54. GRB 240414A: LBT optical detection
  55. GRB 240415A: Swift-XRT refined Analysis
  56. GRB 240421B: AstroSat CZTI detection
  57. GRB240421B: BOOTES-5/JGT optical upper limit
  58. Fermi GRB 240421A: Global MASTER-Net observations report
  59. EP240417a: no counterpart detection by SOAR
  60. EP240420a: Xinglong decaying optical counterpart
  61. GRB 240421B: Swift detection of a burst
  62. EP240420a: Nanshan optical counterpart observations
  63. EP240420a: GWAC-F50A optical upper limit
  64. Fermi trigger No 735280430: Global MASTER-Net observations report
  65. IceCube Alert 240419.98: Global MASTER-Net observations report
  66. GRB 240419B: Swift-XRT refined Analysis
  67. GRB 240419A: Swift-XRT refined Analysis
  68. GRB 240418A: Swift-XRT refined Analysis
  69. GRB 240419B: Swift detection of a burst
  70. EP240417a: YAHPT Optical Upper Limits
  71. GRB240418A: YAHPT Upper Limits
  72. GRB 240419A: VLT optical afterglow detection
  73. GRB 240419A: Swift detection of a burst
  74. Swift GRB240418.85: Global MASTER-Net observations report
  75. GRB 240418A: Swift detection of a burst
  76. Fermi GRB 240417A: Global MASTER-Net observations report
  77. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  78. GRB 240414A: Glowbug gamma-ray detection
  79. EP240416a: EP-WXT detection of a fast X-ray transient
  80. GRB 240414A: AbAO optical upprer limit
  81. GRB 240415A: OHP/T193 optical observations
  82. GRB 240415A: SAO RAS optical observations
  83. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  84. GRB 240414A: Fermi GBM Observation
  85. Fermi GRB 240415A: Global MASTER-Net observations report
  86. GRB 240414B: Fermi GBM Final Real-time Localization
  87. GRB 240415A: Prompt Swift-XRT observations
  88. GRB 240414A: Swift-XRT refined Analysis
  89. GRB240414A : J-band upper limits from WINTER
  90. IPN triangulation of GRB 240410A
  91. Fermi-LAT gamma-ray observations of IceCube-240412A
  92. EP240413a: EP-WXT detection of a fast X-ray transient
  93. GRB 240414A: Swift detection of a burst
  94. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  95. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  96. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  97. EP240408a: GROND detection of a candidate counterpart
  98. EP240408a: Swift follow-up observation
  99. EP240408a: EP-WXT detection of a fast X-ray transient
  100. GRB 240408B: AstroSat CZTI detection

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