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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"

22062 results found.

  1. Fermi trigger No 712718833: Global MASTER-Net observations report
  2. Fermi trigger No 712713532: Global MASTER-Net observations report
  3. Fermi trigger No 712651827: Global MASTER-Net observations report
  4. Swift GRB 230802A: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  6. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  7. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  8. IceCube-230724A: JCMT/SCUBA-2 submm observations
  9. IceCube-230707A: JCMT/SCUBA-2 submm observations
  10. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  12. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  13. Fermi trigger No 712390645: Global MASTER-Net observations report
  14. Fermi-LAT gamma-ray observations of IceCube-230727A
  15. Fermi trigger No 712306969: Global MASTER-Net observations report
  16. IceCube-230727A: No candidates from the Zwicky Transient Facility
  17. GRB 230728A: Swift/UVOT Upper Limits
  18. GRB 230728A: NOT optical observations and possible host galaxy
  19. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  20. Swift GRB230728.12: Global MASTER-Net observations report
  21. GRB 230727A: Swift/BAT-GUANO detection of a burst
  22. Fermi-LAT gamma-ray observations of IceCube-230725A
  23. Fermi-LAT gamma-ray observations of IceCube-230724A
  24. Fermi trigger No 712143685: Global MASTER-Net observations report
  25. Integral GRB230726.26: Global MASTER-Net observations report
  26. GRB 230723B: Further CAHA observations and host galaxy detection
  27. GRB 230723B: ATCA rapid radio follow-up
  28. Integral GRB230725.99: Global MASTER-Net observations report
  29. IceCube Alert 230725.90: Global MASTER-Net observations report
  30. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  31. GRB 230723B: Leavitt Observatory upper limit
  32. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  33. GRB 230723B: Montarrenti Observatory upper limit
  34. GRB 230723B: Optical afterglow candidate from CAHA
  35. GRB 230723B: Bassano Bresciano Observatory upper limit
  36. GRB 230723B: non-detections from Observatoire de Haute-Provence
  37. IceCube Alert 230724.08: Global MASTER-Net observations report
  38. Fermi trigger No 711853834: Global MASTER-Net observations report
  39. Fermi trigger No 711805358: Global MASTER-Net observations report
  40. GRB 230723B: Swift/UVOT Upper Limits
  41. Swift GRB 230723B: Global MASTER-Net observations report
  42. GRB 230723B: Swift-XRT observations
  43. Fermi GRB 230723A: Global MASTER-Net observations report
  44. Swift GRB230720.30: Global MASTER-Net observations report
  45. Fermi trigger No 711088412: Global MASTER-Net observations report
  46. Fermi GRB 230713A: Global MASTER-Net observations report
  47. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  48. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  49. Fermi trigger No 710741042: Global MASTER-Net observations report
  50. IceCube-230707A: No candidates detected by Swift-XRT
  51. IceCube-230707A: No candidates from the Zwicky Transient Facility
  52. Fermi-LAT gamma-ray observations of IceCube-230708A
  53. Fermi-LAT gamma-ray observations of IceCube-230707B
  54. Fermi-LAT gamma-ray observations of IceCube-230707A
  55. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  56. GRB 230707A: Swift-XRT observations
  57. IceCube Alert 230708.35: Global MASTER-Net observations report
  58. IceCube Alert 230707.71: Global MASTER-Net observations report
  59. GRB 230707A: Swift ToO observations
  60. GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
  61. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  62. Fermi GRB 230707A: Global MASTER-Net observations report
  63. Integral GRB230706.70: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  65. ZTF23aaoohpy/AT2023lcr: AMI-LA radio detection
  66. Fermi trigger No 710117592: Global MASTER-Net observations report
  67. GRB 230328B: LBT detection of the likely host galaxy
  68. Konus-Wind detection of GRB 220623A
  69. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  70. GRB 230628E: Swift/UVOT Detection
  71. GRB 230628E: ATCA rapid radio follow-up
  72. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates
  73. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  74. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  75. GRB 230628E - VLT spectroscopic observations
  76. ZTF23aaoohpy/AT2023lcr: LBT observations
  77. Fermi GRB 230628C: Global MASTER-Net observations report
  78. GRB230628E: VLT optical identification of afterglow candidate
  79. Fermi GRB 230628D: Global MASTER-Net observations report
  80. Swift GRB230628.93: Global MASTER-Net observations report
  81. GRB 230628B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  82. LIGO/Virgo/KAGRA S230516az: GOTO candidate counterpart GOTO23hu ruled out by Zwicky Transient Facility observations
  83. ZTF23aaoohpy /AT2023lcr: TNG NIR detection
  84. LIGO/Virgo/KAGRA S230627c: Additional observations from the Zwicky Transient Facility
  85. AT2023lcr: JCMT SCUBA-2 sub-mm observations
  86. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  87. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  88. LIGO/Virgo/KAGRA S230627c: Upper limits from Fermi-GBM Observations
  89. LIGO/Virgo/KAGRA S230627c: Global MASTER-Net observations report
  90. LIGO/Virgo/Kagra S230627c: NED Galaxies in the Localization Volume
  91. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  92. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  93. GRB 230625B: Swift/BAT-GUANO detection of a long burst
  94. GRB 230623A: Swift-XRT observations
  95. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  96. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  97. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  98. GRB 230623B: Swift/BAT-GUANO detection of a long burst outside the coded FOV 
  99. GRB 230623A: Tiled Swift observations
  100. MAXI GRB 230623A: MASTER optical observations

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