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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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

19123 results found.

  1. EP241021a: further SAO RAS optical observations
  2. EP 241026b: LBT optical observations
  3. EP241021a: e-MERLIN radio observation
  4. GRB 241026A: Enhanced Swift-XRT position
  5. EP241026b: EP detection of a fast X-ray transient
  6. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  7. GRB 241026A: SAO RAS observations of possible optical afterglow
  8. GRB 241026A: Swift detection of a burst
  9. GRB241025A: 1.3m DFOT optical afterglow detection
  10. EP241021a: optical follow-up observations with Xinglong Observatory
  11. GRB 241025A: GROWTH-India Telescope optical observations
  12. GRB 241025A: COLIBRÍ Detection of the Afterglow
  13. GRB 241025C: Fermi GBM Detection
  14. IPN triangulation of GRB 241022A (short/hard)
  15. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  16. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  17. GRB 241025A : SVOM/VT optical afterglow observations
  18. EP241021a: Liverpool Telescope optical follow-up observations
  19. GRB 241025A: Enhanced Swift-XRT position
  20. GRB 241025A: DDOTI Afterglow detection
  21. GRB 241025A: TRT optical afterglow observation
  22. GRB 241025A: Swift detection of a burst with an optical counterpart
  23. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  24. GRB 241001A: ATCA radio observations
  25. GRB 241010A: VIRT Optical Upper Limit
  26. EP241021a: SAO RAS optical observations
  27. EP241021a: KAIT optical observations
  28. EP241021a: EP-FXT follow-up observation update
  29. EP241021a: 1.3m DFOT Optical observations
  30. EP241021a: Optical upper limits with Kinder observations
  31. EP241021a: TRT optical observations
  32. GRB 241018A: SVOM/C-GFT optical observations
  33. EP241021a: NOT likely optical counterpart
  34. GRB241017A: 1.3m DFOT optical upper limit
  35. GRB 241018A: 1.3m DFOT Optical upper limit
  36. EP241021a: GOTO optical upper limits
  37. EP241021a: EP detection of a fast X-ray transient
  38. Konus-Wind detection of GRB 241018A
  39. GRB 241018A: SVOM/GRM observation
  40. GRB 241018A/sb24101802: Mephisto optical upper limit
  41. GRB 241017A/sb24101702: Mephisto optical upper limit
  42. GRB 241018A: Mondy optical upper limit
  43. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  44. GRB 241018A: GROWTH-India telescope optical upper limit
  45. GRB241018A: XingLong Optical Upper Limit
  46. GRB 241018A: Swift-XRT observations
  47. GRB 241018A: REM optical/NIR upper limits
  48. GRB 241018A: NOT optical observations
  49. GRB 241018A: SVOM/VT follow-up and optical candidate
  50. GRB 241018A: LCO/0.4m optical upper limits
  51. GRB 241006A: VIRT Optical Upper Limit
  52. GRB 240727A: VIRT Optical Upper Limit
  53. GRB 241018A: X-ray afterglow candidate observed by MXT
  54. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  55. GRB 241017A: GROWTH-India Telescope optical upper limit
  56. GRB241017A: TOO Observations by SVOM/MXT
  57. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  58. GRB 241017A: J-band upper limit from WINTER
  59. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  60. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  61. GRB 240916A: radio detection with the VLA
  62. GRB241013A: REM observations
  63. GRB 241009A: LCO optical upper limits
  64. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  65. GRB 241009A: GRANDMA optical upper limits
  66. GRB 241009A: Swift-XRT afterglow detection
  67. GRB 241010A: JinShan optical observations and potential host galaxy
  68. GRB 241010A: J-band observations with WINTER
  69. GRB 241010A: Enhanced Swift-XRT position
  70. GRB 241010A: LCO optical observations
  71. GRB 241010A: Swift detection of a burst with an optical counterpart
  72. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  73. GRB 241002B: Swift-XRT afterglow detection
  74. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  75. GRB 241002A: NOT optical upper limits
  76. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  77. IceCube-241006A: No candidates from the Zwicky Transient Facility
  78. GRB 241006A: GRANDMA optical upper limits
  79. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  80. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  81. GRB 240910A: LBT optical observations
  82. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  83. GRB 241006A: PRIME near-infrared upper limits
  84. GRB 241006A: Swift/UVOT Upper Limits
  85. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  86. GRB 241001A: Swift-XRT afterglow detection
  87. GRB 241006A: Enhanced Swift-XRT position
  88. GRB 241006A: Swift detection of a burst
  89. GRB 240930B: SVOM/C-GFT optical upper limit
  90. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  91. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  92. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  93. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  94. GRB 241002C: SVOM/C-GFT optical upper limit
  95. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  96. Konus-Wind detection of GRB 240926A
  97. GRB 241002B: PRIME near-infrared detection
  98. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  99. IPN triangulation of GRB 240930B / EP 240930a
  100. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc

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