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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').
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"

32507 results found.

  1. GRB 241025C: VZLUSAT-2 detection
  2. GRB 241025A: VZLUSAT-2 detection
  3. GRB 241018A: cubesat Avion detection
  4. GRB 241030B: TESS detection of optical counterpart
  5. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  6. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  7. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  8. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  9. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  10. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  11. EP241107a: AbAO optical upper limit
  12. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  13. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  14. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  15. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  16. EP241109a: confirmation of a stellar flare by BOOTES-7
  17. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  18. EP241107A: MASTER optical observations of xray transient
  19. EP241107a: KAIT optical observations
  20. GRB 241108A: Swift ToO observations
  21. GRB 241030A: TESS observations
  22. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  23. EP241107a: Kinder optical follow-up observations
  24. GRB 241025A: radio detection with the VLA
  25. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  26. EP241107a: AKO Optical Afterglow Follow-Up Observations
  27. EP241107a: GSP detects optical counterpart
  28. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  29. GRB 241105A: EP-FXT follow-up observations
  30. GRB 241105A: SVOM/GRM observation
  31. EP241107a: OHP/T193 photometric and spectroscopic observations
  32. GRB 241105a: PRIME near-infrared upper limits
  33. EP241107a: FTW Optical and NIR observations of the optical counterpart
  34. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  35. EP241107a: GIT optical observations
  36. EP241107a: Global MASTER-Net observations report
  37. EP241107a: SVOM/C-GFT optical observations
  38. EP241107a: AKO Optical Afterglow Detection
  39. GRB 241025A: LBT optical observations
  40. GRB241105A: Gemini-South Optical Afterglow Detection
  41. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  42. GRB 241105A: Swift/UVOT Detection
  43. EP241101a: CrAO ZTSH optical observations
  44. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  45. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  46. GRB 241030A: Mondy optical observations
  47. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  48. Konus-Wind detection of GRB 241105A (short with extended emission)
  49. Konus-Wind detection of GRB 241021A
  50. GRB 241105A: SVOM/VT optical afterglow observations
  51. GRB 241105A: Swift-XRT afterglow detection
  52. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  53. GRB 241104A: Swift-XRT observations
  54. GRB 240511A: LCO upper limits
  55. GRB 241104A: Fermi GBM Observation
  56. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  57. GRB 241105A: Swift ToO observations
  58. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  59. GRB 241104A: Swift ToO observations
  60. GRB 241104A: NOT optical non-detection
  61. GRB 241105A: GOTO tentative optical counterpart candidate
  62. Fermi GRB 241105A: Global MASTER-Net observations report
  63. GRB 241104A: SVOM/VT optical candidate
  64. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  65. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  66. GRB 241104A: SVOM/GRM observation
  67. EP241104a: EP detection of GRB 241104A X-ray emission
  68. GRB 241010A: host galaxy redshift z = 0.977
  69. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  70. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  71. GRB 240821A: further radio observations with the VLA
  72. Fermi GRB 241104A: Global MASTER-Net observations report
  73. GRB 241030A: GRBAlpha detection
  74. EP241101a: EP-FXT observations update
  75. EP241103a: GIT optical upper limit
  76. EP241021a: OHP/T193 further optical observations
  77. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  78. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  79. EP241103a: GOTO optical upper limit
  80. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  81. EP241101a: Possible detection of an optical counterpart with FTW
  82. EP241103a: Swift XRT detection and improved X-ray position
  83. EP241021a: continued SOAR observations
  84. EP241101a: Optical upper limits with Kinder observations
  85. EP241101a: OHP/T193 optical observations
  86. EP241103a: Gemini optical limits
  87. EP241103a: EP observation update
  88. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  89. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  90. EP241103a: GSP optical upper limit
  91. EP241103A: LCO optical observations
  92. EP241103a: Global MASTER-Net observations report
  93. GRB 241030A: Rapid release of TESS data.
  94. EP241101a: Global MASTER-Net observations report
  95. GRB 241029A: GRBAlpha detection
  96. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  97. S241102cy: Identification of a GW compact binary merger candidate
  98. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  99. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  100. GRB241030A: OHP/T193 optical observations

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