A Tale of Three Black Holes

astrofotografie, astronomie, astronomy, astrophotography, binary system, black hole, gaia, gaia bh1, ophiuchus, star, stars, stern, sterne
Gaia BH1 Starfield in Ophiuchus – LRGB v1
astrofotografie, astronomie, astronomy, astrophotography, binary system, black hole, centaurus, gaia, gaia bh2, star, stars, stern, sterne, zentaur
Gaia BH2 Starfield in Centaurus – LRGB v1
adler, aquila, astrofotografie, astronomie, astronomy, astrophotography, binary system, black hole, gaia, gaia bh3, star, stars, stern, sterne
Gaia BH3 Starfield in Aquila – LRGB v1

With #3 recently discovered in the analysis during preparation of Gaia DR4 data, there are now 3 black holes in the Gaia catalog. Or more precise, 3 binary systems consisting of a companion star and a likely stellar-mass black hole.

So I took the opportunity to capture the corresponding starfields with the new IAS remote telescope “Dieter” at Hakos, Namibia. The images only show the companion stars, of course. ;-)

Regarding the BH3 image, at first I wasn’t sure whether I found the right object, as the catalog gives the coordinates RA=19h39m18.7115472s, DEC=+14d55m54.010992s and the read-out in Pixinsight showed ICRS RA=19h39m18.68s, DEC=+14d55m50.3s. But thanks to the discussion with Ulrich Bastian I found out that it is necessary to take into account the large proper motion of the object, which results in almost 4″ deviation in declination. Calculating the current position for 2024.5 with Astropy yields RA=19h39m18.66368537s DEC=+14d55m50.2085012s.

Gaia BH1

(Gaia DR3 4373465352415301632) A binary system consisting of a G-type star and a stellar-mass black hole, approx. 9.6 M☉, distance 1560 ly, the nearest of the three, located in the constellation Ophiuchus.

Catalog position (ICRS) = 17h28m41.09661261s -00d34m51.52337796s

Gaia BH2

(Gaia DR3 5870569352746779008) A binary system consisting of a red giant and a stellar-mass black hole, approx. 8.9 M☉, distance 3800 ly, located in the constellation Centaurus.

Catalog position (ICRS) = 13h50m16.74776018s -59d14m20.33070104s

Gaia BH3

(Gaia DR3 4318465066420528000) A binary system consisting of a G-type giant star and a stellar-mass black hole, approx. 32.7 M☉, the heaviest known stellar black hole in the Milky Way, distance 1926 ly, located in the constellation Aquila.

Catalog position (ICRS) = 19h39m18.7115472s +14d55m54.010992s

IAS – Internationale Amateursternwarte e.V. – Hakos Observatory, Namibia
IAS remote telescope “Dieter”
Lacerta 12″ Newton f/4, ASA DDM85XL-A, QHY268M, Baader LRGB filters

BH1: 30x L, 10x R, 10x G, 10x B 120s, mode 1, gain 56, offset 10, -5C, 20 flats, 30 darks, 50 bias, total time: 7200s / 2h

BH2: 26x L, 10x R, 10x G, 9x B 120s, mode 1, gain 56, offset 10, -5C, 20 flats, 30 darks, 50 bias, total time: 6600s / 1h50

BH3: 30x L, 10x R, 10x G, 10x B 120s, mode 1, gain 56, offset 10, -5C, 20 flats, 30 darks, 50 bias, total time: 7200s / 2h

Data acquisition: IAS remote team / Martin Junius
Data calibration/integration: PixInsight WBPP
Image processing: PixInsight, BlurXTerminator, Lightroom, 50% crop