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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').

9604 results found.

  1. EP240426b: EP-WXT detection of a new fast X-ray transient
  2. GRB 240426A: AstroSat CZTI detection
  3. XMM-Newton observation of EP240426a
  4. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  5. EP240426a: GMG optical upper limit
  6. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  7. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  8. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  9. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  10. GRB 240425A: Fermi GBM Final Real-time Localization
  11. Fermi trigger No 735697285: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  13. LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up
  14. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  15. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  16. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  17. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  18. IceCube Alert 240424.08: Global MASTER-Net observations report
  19. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  20. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  21. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  22. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  23. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  24. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  25. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  26. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  28. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  29. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  30. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  31. Fermi-LAT gamma-ray observations of IceCube-240419A
  32. GRB 240414A: AMI-LA radio observations
  33. GRB 240414A: LBT optical detection
  34. GRB 240415A: Swift-XRT refined Analysis
  35. GRB 240421B: AstroSat CZTI detection
  36. GRB240421B: BOOTES-5/JGT optical upper limit
  37. Fermi GRB 240421A: Global MASTER-Net observations report
  38. EP240417a: no counterpart detection by SOAR
  39. EP240420a: Xinglong decaying optical counterpart
  40. GRB 240421B: Swift detection of a burst
  41. EP240420a: Nanshan optical counterpart observations
  42. EP240420a: GWAC-F50A optical upper limit
  43. Fermi trigger No 735280430: Global MASTER-Net observations report
  44. IceCube Alert 240419.98: Global MASTER-Net observations report
  45. GRB 240419B: Swift-XRT refined Analysis
  46. GRB 240419A: Swift-XRT refined Analysis
  47. GRB 240418A: Swift-XRT refined Analysis
  48. GRB 240419B: Swift detection of a burst
  49. EP240417a: YAHPT Optical Upper Limits
  50. GRB240418A: YAHPT Upper Limits
  51. GRB 240419A: VLT optical afterglow detection
  52. GRB 240419A: Swift detection of a burst
  53. Swift GRB240418.85: Global MASTER-Net observations report
  54. GRB 240418A: Swift detection of a burst
  55. Fermi GRB 240417A: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  57. GRB 240414A: Glowbug gamma-ray detection
  58. EP240416a: EP-WXT detection of a fast X-ray transient
  59. GRB 240414A: AbAO optical upprer limit
  60. GRB 240415A: OHP/T193 optical observations
  61. GRB 240415A: SAO RAS optical observations
  62. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  63. GRB 240414A: Fermi GBM Observation
  64. Fermi GRB 240415A: Global MASTER-Net observations report
  65. GRB 240414B: Fermi GBM Final Real-time Localization
  66. GRB 240415A: Prompt Swift-XRT observations
  67. GRB 240414A: Swift-XRT refined Analysis
  68. GRB240414A : J-band upper limits from WINTER
  69. IPN triangulation of GRB 240410A
  70. Fermi-LAT gamma-ray observations of IceCube-240412A
  71. EP240413a: EP-WXT detection of a fast X-ray transient
  72. GRB 240414A: Swift detection of a burst
  73. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  74. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  75. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  76. EP240408a: GROND detection of a candidate counterpart
  77. EP240408a: Swift follow-up observation
  78. EP240408a: EP-WXT detection of a fast X-ray transient
  79. GRB 240408B: AstroSat CZTI detection
  80. Fermi GRB 240407A: Global MASTER-Net observations report
  81. Fermi-LAT gamma-ray observations of IceCube-240327B
  82. Fermi-LAT gamma-ray observations of IceCube-240327A
  83. GRB 240331A: GRBAlpha detection
  84. Konus-Wind detection of LXT 240402A/GRB 240402B
  85. LXT 240402A: MASTER optical observations with AGN in error-box
  86. Fermi GRB 240402A: Global MASTER-Net observations report
  87. X-ray transient EP240331a: Kinder optical upper limits
  88. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  89. EP240331A: MASTER optical observations
  90. X-ray transient EP20240331a: MeerLICHT optical upper limits
  91. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  92. GRB 240324A: AstroSat CZTI detection of a short burst
  93. GRB 240331A: AstroSat CZTI detection
  94. GRB 240329A: AstroSat CZTI detection
  95. X-ray transient EP240315a: continued ATCA monitoring
  96. X-ray transient EP240315a: e-MERLIN radio observations
  97. GRB 240320A: Glowbug gamma-ray detection
  98. Fermi GRB 240320A: Global MASTER-Net observations report
  99. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  100. Fermi trigger No 732657380: Global MASTER-Net observations report

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