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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.

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

24617 results found.

  1. GRB 250101a: Liverpool Telescope optical follow-up
  2. GRB 250103B: Swift detection of a burst
  3. GRB 250103A: Xinglong 2.16m Optical Candidate
  4. GRB 250101B: SVOM/GRM observation
  5. GRB 250103A: GOTO optical upper limit
  6. GRB 250103A: SVOM/C-GFT optical upper limit
  7. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  8. EP241231b: optical upper limit with the Liverpool Telescope
  9. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  10. GRB 250103A: SVOM detection of a long burst
  11. EP250101a: Xinglong optical upper limit
  12. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  13. GRB 250101A: Swift-BAT refined analysis
  14. GRB 250101A: further SAO RAS optical observations
  15. GRB 250101A: LCO optical counterpart detection
  16. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  17. GRB 250101A: Swift/UVOT Detection
  18. GRB 250101A: 1.6m Mephisto multi-band optical followup
  19. GRB 250101A: Swift-XRT refined Analysis
  20. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  21. GRB 250101A: LCOGT optical afterglow detection
  22. GRB 250101A: OASDG optical observations
  23. GRB 250101B: Fermi GBM Final Real-time Localization
  24. GRB 250101A: SAO RAS observations of optical brightening
  25. GRB 250101A: BOOTES-4/MET optical afterglow detection
  26. GRB 250101A: AKO Optical Afterglow Detection
  27. GRB 250101A: SAO RAS optical observations
  28. GRB 250101A: Enhanced Swift-XRT position
  29. LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
  30. GRB 250101A: SVOM/C-GFT early optical observations
  31. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  32. GRB 250101A: Nanshan/HMT optical observations
  33. GRB 250101A : GIT optical detection
  34. GRB 250101A: GMG Optical Observation
  35. GRB 250101A: Swift detection of a burst with an optical counterpart
  36. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  37. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  38. GRB 241229B: Continued CrAO ZTSh observations
  39. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  40. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  41. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  42. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  43. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  44. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  45. GRB 241229B: SVOM/GRM observation
  46. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  47. EP241217A: J band upper limit by SYSU 80cm telescope
  48. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  49. GRB 241229B: SAO RAS optical upper limit
  50. GRB 241228B: SAO RAS optical observations
  51. GRB 241229A: SAO RAS optical observations
  52. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 241229A: Swift-XRT observations
  54. EP240702a: 7DT Optical upper limits
  55. GRB 240606B: 7DT Optical upper limits
  56. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  57. GRB 241229B: Swift-BAT refined analysis
  58. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  59. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  60. GRB241229B: UVOT upper limits
  61. GRB 241228B: Fermi GBM Observation
  62. GRB 241228B: Swift-XRT afterglow detection
  63. GRB 241229B: Fermi GBM Observation
  64. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  65. GRB 241228A: Mondy optical afterglow observations
  66. GRB 241229A: GOTO optical upper limits
  67. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  68. GRB 241228A: NOT optical upper limits
  69. GRB 241228B: LCO optical observation
  70. GRB 241228A: Swift-BAT refined analysis
  71. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 241228A: Fermi GBM Observation
  73. GRB241228B: GROWTH-India Telescope optical observations
  74. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  75. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 241228A: GROWTH-India telescope optical upper limit
  77. GRB 241228B: TRT optical counterpart confirmation
  78. GRB 241228A: Swift-XRT refined Analysis
  79. GRB 241228A: Swift/UVOT Upper Limits
  80. GRB 241228A: Enhanced Swift-XRT position
  81. GRB 241228A: Swift detection of a burst
  82. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  83. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  84. GRB 241212A: VZLUSAT-2 detection
  85. EP241223a: Mondy AZT-33IK optical observations
  86. GRB 241029A: LCO optical observation
  87. GRB 241223A: Swift-XRT observations
  88. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  89. GRB 241029A: AbAO AS-32 optical observations
  90. GRB 241223A: Fermi GBM Detection
  91. Fermi trigger No 756678579: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  93. EP241223a
  94. EP241223a: EP-WXT detection of a fast X-ray transient
  95. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  96. GRB241113A: 7DT Optical upper limits
  97. GRB 241223A: GOTO optical observations summary
  98. GRB 241105A: JWST photometric observations of the host galaxy
  99. EP241217a: e-MERLIN radio observations
  100. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)

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