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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

28282 results found.

  1. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  2. GRB 241229B: Continued CrAO ZTSh observations
  3. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  4. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  5. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  6. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  7. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  8. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  9. GRB 241229B: SVOM/GRM observation
  10. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  11. EP241217A: J band upper limit by SYSU 80cm telescope
  12. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  13. GRB 241229B: SAO RAS optical upper limit
  14. GRB 241228B: SAO RAS optical observations
  15. GRB 241229A: SAO RAS optical observations
  16. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 241229A: Swift-XRT observations
  18. EP240702a: 7DT Optical upper limits
  19. GRB 240606B: 7DT Optical upper limits
  20. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  21. GRB 241229B: Swift-BAT refined analysis
  22. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  23. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  24. GRB241229B: UVOT upper limits
  25. GRB 241228B: Fermi GBM Observation
  26. GRB 241228B: Swift-XRT afterglow detection
  27. GRB 241229B: Fermi GBM Observation
  28. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  29. GRB 241228A: Mondy optical afterglow observations
  30. GRB 241229A: GOTO optical upper limits
  31. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  32. GRB 241228A: NOT optical upper limits
  33. GRB 241228B: LCO optical observation
  34. GRB 241228A: Swift-BAT refined analysis
  35. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  36. GRB 241228A: Fermi GBM Observation
  37. GRB241228B: GROWTH-India Telescope optical observations
  38. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  39. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  40. GRB 241228A: GROWTH-India telescope optical upper limit
  41. GRB 241228B: TRT optical counterpart confirmation
  42. GRB 241228A: Swift-XRT refined Analysis
  43. GRB 241228A: Swift/UVOT Upper Limits
  44. GRB 241228A: Enhanced Swift-XRT position
  45. GRB 241228A: Swift detection of a burst
  46. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  47. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  48. GRB 241212A: VZLUSAT-2 detection
  49. EP241223a: Mondy AZT-33IK optical observations
  50. GRB 241029A: LCO optical observation
  51. GRB 241223A: Swift-XRT observations
  52. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  53. GRB 241029A: AbAO AS-32 optical observations
  54. GRB 241223A: Fermi GBM Detection
  55. Fermi trigger No 756678579: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  57. EP241223a
  58. EP241223a: EP-WXT detection of a fast X-ray transient
  59. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  60. GRB241113A: 7DT Optical upper limits
  61. GRB 241223A: GOTO optical observations summary
  62. GRB 241105A: JWST photometric observations of the host galaxy
  63. EP241217a: e-MERLIN radio observations
  64. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  65. The EP-WXT trigger 01709129287 is likely a flaring star
  66. EP241217a: Liverpool Telescope optical upper limit
  67. EP241021a: VLA radio detection
  68. GRB 241218A: Mondy AZT-33IK optical upper limit
  69. EP241217a : Leavitt Observatory optical upper limit
  70. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  71. EP241217a: 1.6m Mephisto multi-band optical observations
  72. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  73. GRB 241218A: Swift/UVOT Upper Limits
  74. EP241217a: optical upper limit with the Liverpool Telescope
  75. GRB 241209B: EP-FXT afterglow detection
  76. GRB 241218A: NOT optical upper limits
  77. GRB 241218A: Swift-BAT refined analysis
  78. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  79. EP 241217a: NIR detection with P200/WIRC
  80. EP 241217a: Possible J-band detection with WINTER
  81. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  82. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  83. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  84. GRB 241217A / EP241217b: NOT optical upper limits
  85. GRB 241218A: REM optical upper limit
  86. GRB 241217A/EP241217b: REM optical/NIR upper limits
  87. EP241217a: REM optical/NIR upper limits
  88. GRB 241217a: Liverpool Telescope optical follow-up
  89. EP241217a: Liverpool Telescope optical follow-up
  90. GRB 241218A: Swift-XRT refined Analysis
  91. EP241217a: NOT optical observations
  92. EP241217a: GROWTH-India Telescope optical observations
  93. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  94. EP241119a: 7DT Optical upper limits
  95. EP241217a: Xinglong optical follow-up observations
  96. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  97. GRB 241218A: LCOGT Optical Upper Limit
  98. GRB 241218A: Enhanced Swift-XRT position
  99. GRB 241217A: GMG Optical Upper Limit
  100. GRB 241218A: Swift detection of a burst

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