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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.

"N/A_MC170219_R1" does not adhere to advanced search syntax. Please refer to the documentation and try again.
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"

10917 results found.

  1. GRB 251221A: PRIME near-infrared observation
  2. GRB 251221A: UAFO and Mondy optical upper limit
  3. GRB 251220A: MAXI/GSC detection
  4. IceCube-251218A: COLIBRÍ optical upper limits
  5. GRB 251214B: VIRT Optical Upper Limit
  6. GRB 251202A/EP251202a: Koshka optical upper limit
  7. GRB 251214B: Mondy optical upper limit
  8. EP251214a: Optical upper limit with Kinder observations
  9. GRB 251214B: UAFO optical upper limit
  10. GRB 251202A: radio detection with the VLA
  11. GRB 251214B: AbAO optical observations
  12. GRB 251203B: AbAO optical observations
  13. GRB 251214B : MASTER optical afterglow detection
  14. GRB 251214B: Swift detection of a burst with an optical counterpart
  15. EP251124a: Mondy optical upper limit
  16. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  17. EP251130a: Mondy and AbAO optical observations
  18. GRB 251208B: Fermi-LAT detection
  19. GRB 251206A: SVOM detection of a burst through offline search
  20. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  21. GRB 251205A: Swift/UVOT Detection
  22. GRB 251203C: Swift/UVOT Upper Limit
  23. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  24. GRB 251205A: NOT optical observations
  25. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  26. Swift GRB 251205A : MASTER OT detection with host galaxy
  27. GRB 251205A: Swift detection of a burst with an optical afterglow
  28. GRB 251203C: SVOM/ECLAIRs refined analysis
  29. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  30. GRB 251203C: LCO optical afterglow confirmation
  31. GRB 251203C: SVOM/VT optical counterpart
  32. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  33. GRB 251203C: LCO optical upper limits
  34. GRB 251203B: LCO optical upper limits
  35. GRB 251203C: SVOM detection of a burst
  36. GRB 251203B: SVOM detection of a burst
  37. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  38. GRB 251202A / EP251202a: SVOM/VT optical observation
  39. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  40. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  41. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  42. GRB 251126A: SAO RAS optical marginal detection
  43. GRB 251126A: SVOM/VT optical observation
  44. EP251130a: SVOM/VT optical observation
  45. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  46. GRB 251201B: SVOM/VT optical fading
  47. Swift GRB 251201B : MASTER optical counterpart detection
  48. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  49. EP251130a: Mondy optical observations
  50. EP251130a: Optical detections with Kinder observations
  51. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  52. GRB 251201A: MAXI/GSC detection
  53. GRB 251129A / EP251129a: OSN and CAHA optical follow-up
  54. GRB 251129A / EP251129a: SAO RAS optical observations
  55. GRB 251126A: SAO RAS optical observations
  56. SVOM GRB 251129A : MASTER optical counterpart detection
  57. Swift trigger 1418333 is not an astrophysical source
  58. GRB 251129A / EP251129a: SVOM/VT optical fading
  59. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  60. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  61. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  62. GRB 251126A: further SAO RAS optical observations
  63. GRB 251126A: Mondy and SAO RAS optical observations
  64. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  65. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  66. EP251124b follow-up observation by EP-FXT
  67. EP251124b: NOT r- and z-band optical upper limits
  68. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  69. EP251124a: Xinglong GWAC-F60A optical observation
  70. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  71. EP251124a: NOT r- and z-band optical upper limits
  72. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  73. EP251124a: Optical upper limit with Kinder observations
  74. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  75. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  76. EP251124a: Einstein Probe detection of an X-ray transient
  77. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  78. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  79. EP251118a: Continued Optical Detection with Kinder observations
  80. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  81. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  82. EP251118a: Optical detection with Kinder observations
  83. EP-WXT trigger 01709248403: confirmation of a stellar flare by SVOM/VT
  84. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  85. EP251118a / GRB 251118C: SVOM/VT optical observation
  86. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  87. EP251118A / GRB 251118C : MASTER optical counterpart observations
  88. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  89. GRB 251117A: Fermi-LAT detection
  90. GRB 251116C: Swift/BAT arcminute localization of a burst
  91. GRB 251116B: SVOM/VT optical upper limit
  92. EP251023a: Assy AZT-20 optical observations
  93. EP251023a: UAFO and AbAO optical observations
  94. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  95. GRB 251116C: SVOM/VT optical upper limit
  96. GRB 251025B: further Mondy optical observations
  97. GRB 251111A: Mondy optical upper limit
  98. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  99. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  100. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates

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