Table 2
Parameters of the GC NGC 6749 and the NGC 6749A system.
| Globular cluster parameters | |
| Right ascension, αGC (J2000) | 19:05:15.36 |
| Declination, δGC (J2000) | 01:54:3.6 |
| Distance, D (kpc) |  |
| Proper motion in α, μα,GC(mas yr−1) | −2.829 ± 0.028 |
| Proper motion in δ, μδ,GC(mas yr−1) | −6.006 ± 0.027 |
| Core radius (arcmin) | 0.62 |
| Central velocity dispersion, σv (km s−1) | 2.64 |
| Escape velocity, Vssc (km s−1) | 11.8 |
| aGC (10−9ms−2) | −0.218 |
| Definitions of the timing solution | |
| Terrestrial time standard | TT(BIPM2023) |
| Time units | TDB |
| Solar system ephemeris | DE440 |
| Span of timing data (MJD) | 53 070-60 617 |
| Reference epoch (MJD) | 60378 |
| Number of TOAs | 253 |
| Weighted rms residual (μs) | 27.8 |
| χ2 | 235.3 |
| Reduced χ2 (χ2/nfree) | 1.006 |
| Reduced Weighted rms residual (μs) | 27.8 |
| Spin and astrometric parameters | |
| Right ascension, α (J2000) | 19:05:14.69052(19) |
| Declination, δ (J2000) | 01:54:48.274(8) |
| Proper motion in α, μα(mas yr−1) | −2.52(24) |
| Proper motion in δ, μδ (mas yr−1) | −9.4(8) |
| Spin frequency, ν (Hz) | 313.190896837(10) |
| First spin frequency derivative, ν̇ (10−15 Hz s−1 ) | −1.885(17) |
| Dispersion measure, DM (cm−3 pc) | 195.0(3.3) |
| First DM derivative, DM001 (cm−3 pc yr−1 ) | 0.06(36) |
| Second DM derivative, DM002 (cm−3 pc yr−2) | 0.012(21) |
| Third DM derivative, DM003 (cm−3 pc yr−3 ) | 0.0054(9) |
| Fourth DM derivative, DM004 (cm−3 pc yr−4) | 0.00069(13) |
| Orbital parameters | |
| Orbital period, Pb (day) | 0.8125524389(21) |
| Projected semi-major axis of pulsar orbit, x ≡ ap sin i/c (s) | 0.5886568(41) |
| Time of ascending node, Tasc | 60378.0292965(21) |
| ε1 ≡ e sin ω | −0.000031(13) |
| ε2 ≡ e cos ω | 0.000002(12) |
| Observed orbital period derivative, Ṗb(10−12s s−1) | 0.4(6) |
| Optical parameters of companion WD | |
| Reddening-corrected F606W magnitude, mF606W | 26.08(6) |
| Reddening-corrected F814W magnitude, mF814W | 24.78(5) |
| White dwarf temperature | 11 600-14.800 |
| White dwarf mass (M⊙) | 0.17-0.19 |
| Cooling age (Gyr) | 0.4-0.7 |
| Derived parameters | |
| Galactic longitude of the cluster centre, ℓ (deg) | 36.201 |
| Galactic latitude of the cluster centre, b (deg) | −2.205 |
| DM Distance, dNE2001 (kpc) | 3.4 |
| DM Distance, dYMW16 (kpc) | 5.5 |
| DM Distance, dNE2025 (kpc) | 3.8 |
| Offset of pulsar from the centre of the cluster (′) | 0.76 |
| Offset of pulsar from the centre of the cluster (core radii) | 1.25 |
| Projected distance of from the centre of the cluster (pc) | 1.6 |
| Total proper motion, μT (mas yr−1) | 9.7(7) |
| Position angle of proper motion, J2000, Θμ (deg) | 195.0(18) |
| Proper motion relative to the cluster (mas yr−1) | 3.5(8) |
| Transverse velocity relative to the cluster (km s−1) | 123(34) |
| Spin period, P (ms) | 3.19294082330(10) |
| Spin period derivative, Ṗobs (10−20s s−1) | 1.922(17) |
| Cluster contribution to Ṗobs (10−20s s−1) | ±0.18 |
| Galactic acceleration contribution to Ṗobs (10−20s s−1) | −0.23 |
| Proper motion contribution to Ṗobs (10−20s s−1) | +0.52 |
| Intrinsic spin period derivative, Ṗint (10−20s s−1) | 1.64±0.18 |
| Characteristic age (Gyr) | 2.8-3.5 |
| Surface magnetic field (108 G) | 2.2-2.4 |
| Orbital eccentricity, e | 0.000032(12) |
| Epoch of periastron, T0 (MJD) | 60378.667(55) |
| Longitude of periastron, ω (deg) | 282(25) |
| Mass function f(M⊙) | 0.000331716(7) |
| Minimum companion mass, Mc,min | 0.088 |
| Median companion mass, Mc,med | 0.103 |
| Orbital inclination for mc = 0.18M⊙ | 30.7 |
Notes. The timing parameters were derived using TEMPO with the ELL1H binary model. The values in the parenthesis indicate the 1σ uncertainties on the last digit. The minimum and median companion masses and orbital inclination are estimated assuming a pulsar mass of 1.35 M⊙. The linear distances and velocities relative to the centre of the GC assume the distance estimated for the GC.
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