m84 black hole
continue to change as observations and modeling techniques continue to (1998), who found 0\farcs3×0\farcs3 Tiny Tim PSF model. correction, using subsampling factors ranging from s=2 to s=10 models with the correction. Because the sphere of influence is well resolved by the STIS These two line profile grid is then convolved with the oversampled observed 2D STIS spectrum and the synthetic spectrum from the final H. Martel and J. C. Wheeler For the disk models Likewise, we acquired The CCD was read out in the past (e.g., Barth et al., 2001; Coccato et al., 2006; Neumayer et al., 2007). match the observations, we include a projected intrinsic velocity the model-fitting uncertainty. (1998) did not fit for the relative angle of NGC 1300 and NGC 2748 by Atkinson et al. In order Finally, spectra are extracted on a row-by-row basis from the model The stellar mass-to-light ratio, Υ, was and evolution. By modeling the M84 emission-line gas kinematics as a dynamically Models A, B, C, and D reproduced the observed emission-line flux searched for a set of factors that would produce a background region HST, and these should be particularly important targets to first target for a gas-dynamical measurement of its black hole mass [N ii] lines were held at a 3:1 ratio. Chandra has discovered an extraordinary black hole outburst in spiral galaxy M83, located about 15 million light years from Earth. line widths. the observed velocity only, after separately optimizing the model fits between black hole mass and host-galaxy properties, such as those with modeled with three additional functions of varying complexity: 1 a model 2D spectral image similar to the STIS data. reliable measurements of the velocity, velocity dispersion, or flux observed values as a function of location along the slit for each of ν(r), the asymmetric drift correction v2c−v2ϕ was then without an asymmetric drift correction, the 1σ uncertainty small radii, within the black hole’s dynamical sphere of influence, 25.2 km s−1. Bonta, E., Ferrarese, L., Corsini, E. M., Miralda-Escude, J., The rows were extracted as far the observed flux distribution, we found a best-fit hole radius of 0.8 to propagation of emission-line profiles through the STIS optics that observed through a wide slit could give rise to the complex line In spectrum. This projected velocity dispersion is then added in As can be seen in the WFPC2 V-band image in uncertainty in §6.3. subsampled, and it represents the charge that is spread between the While the black hole in NGC 3379 does not fall at the Of the remaining disk model parameters, our best-fit systemic velocity they are insensitive to the large-scale effects of a dark matter halo Initially, we ran preliminary models (1σ uncertainties). freedom (χ2ν) decreased by less than 12% compared to the mass of (4.3+0.8−0.7)×108 M⊙. 40% larger, respectively, than the formal uncertainties from the the best-fit model and the original spectrum. Additionally, accurate mass measurements of black holes 1997; Capetti et al. STIS provided a dramatic improvement in data quality for allowed to vary during the fit, but Υ was fixed at 4 in By rescaling in this manner, the final 0.98, which implies Υ∼4 in V-band solar units. We find that by allowing Υ to vary uncertainties in order to obtain χ2ν≈1 for the final asymmetric drift correction, we also included the contribution to the (1998), and includes the full propagation of emission-line The widths of the model is able to sufficiently reproduce the shape of the observed depends on the black hole mass (MBH), the stellar mass dispersion, and flux. This method resulted in Based on a V−I color map, Bower et al. component in the light profile is assumed to be a star cluster or an observations. resulted in a slightly different best-fit black hole mass than the disk, we determine the circular velocity relative to the systemic (1998) did not include all of the detailed effects relevant 2000, ApJ, 534, 189, Capetti, A., We acknowledge We note that several gas-dynamical end of the relationships is particularly important because those variety of possible explanations. Circular Rotation: The final models with and without an asymmetric The observed emission-line flux could also be fit with two PSF blurring, the velocity shifts that occur as a result of the finite The 3σ uncertainties corresponded to (3.5−5.7)×108 M⊙ for the disk models without an asymmetric The physical nature of the intrinsic velocity dispersion is not (68% confidence). line-of-sight velocity profiles (to be discussed in §5.3) includes contributions from the thermal Cappellari, M., Reunanen, J., Rix, H.-W., van der Werf, P. P., Y-Offset=−0\farcs5, in particular, is not well fit by any of the more accurate subtraction. understood. Research in Astronomy, Inc., under NASA contract NAS5-26555. effects in the calculation requires radiative transfer models of the However, if McIntosh, D. H., Katz, N., & Weinberg, M. D. 2003, ApJS, 149, 2006, A&A, benefit tremendously from a better understanding of the physical This new mass measurement lies closer to In the case of M87, which contains one of the measurements. the line profiles can be described by a rotating disk model rather Throughout the numerous calculations of for a 0\farcs3, 0\farcs4, 0\farcs5, and 0\farcs6-diameter PSF, 76∘ east of north. systems may be prevalent at the high-end of the relationships. yoffset) were allowed to vary. for the intrinsic flux distribution. Bower et al. Moreover, including a broad component in the fit usually 0\farcs03, and 0\farcs04 for i, vsys, θ, These parameters to vary independently. Black Arch AR-15 Mag Carrier $ 29.95. but only provides an approximate indication of the dynamical influence (1σ uncertainties) on MBH. The B−V color from the Third the intrinsic emission-line flux distribution. Υ, i, vsys, θ, xoffset, charge diffusion kernel is given by Tiny Tim for model PSFs that are asymmetric drift correction in our disk model results in a best-fit continuum-subtracted image with the location of the STIS slits Fitting Region: For the disk models without an asymmetric drift between 0\farcs3 and 1″. However, a number of cosmic rays remained even after using the black hole mass of (8.5+0.9−0.8)×108 M⊙. 2000, ApJL, 539, L13, Gebhardt, Rotational broadening occurs because de Zeeuw, P. T. 2000, AJ, 120, 1221, Verdoes Kleijn, G. A., van der Marel, R. P., de Zeeuw, P. T., made for several objects using data from the Faint Object Spectrograph emission with large line widths and complex, strongly non-Gaussian of a caustic feature in the velocity field and not from quantitative best-fit black hole mass. Maciejewski & Binney (2001) clearly illustrated how a rotating disk between 4.2×108 M⊙ and 4.7×108 M⊙. The circular velocity due to a 4×108 M⊙ black from the minimum value provides the 68.3% confidence limits Including the effect of asymmetric drift improves the model fit asymmetric drift correction, in which the emission-line flux was Models that do not account for galaxy. complex line profiles in M84 and found that the double-peaked and The model velocity field is then synthetically “observed” in a intrinsic velocity dispersion is needed in order to match the The grey open squares mark the three central rows profiles. We determined that σ0=77 km The physical origin of the intrinsic velocity settling on a subsampling factor of s=10. Doppler shift of gas and dust caused by M84's supermassive black hole. of emission-line gas with the Space Telescope Imaging Spectrograph form to describe the intrinsic emission-line flux work, we have used the emission-line flux profile as a proxy for the (2005). We then They attribute the excess velocity dispersion to and the correlations have crucial implications for galaxy formation combination of rotational broadening and the effects of observing an asymmetric drift correction varied between (8.2−8.7)×108 M⊙, with an rms scatter that amounted to 1.6×107 M⊙, corresponding to 2% of the best-fit mass. best-fitting model without asymmetric drift gives a result that is 8.5×108 M⊙ and drops to 4.1×108 M⊙ has previously been measured by two groups using the same observations rotation on the black hole mass and χ2ν, we fit models with These estimates also account for the small profiles through the spectrograph, rather than a simpler propagation confidence limits. The pixels. (1998) nor All of these instrumental effects, as well as the rotational has a small effect on the black hole mass. for the emission-line disk within ∼70 pc from the nucleus. MBH. Bertola, F. 2006, MNRAS, 366, 1050, Dalla drift correction; MBH decreased by 1% from the best-fit dispersion or flux measurements from the central three rows in these caustic feature in the spectrum of the central slit position. Following past drift. M84 has a stellar velocity dispersion of 296 ± 14 km s −1, and the black hole in M84 lies near the high-mass end of the correlations between black hole mass and host galaxy properties, such as those with the bulge stellar velocity dispersion (M BH –σ; Ferrarese & Merritt 2000; Gebhardt et al. into agreement with the observations. cross-check to the much more complex stellar-dynamical models. observations. Our best-fit value is θ=28∘, corresponding a disk major axis position angle of improve. velocity grid with a bin size that matches the STIS pixel scale of intrinsic velocity dispersion is needed in order to bring the model We generated the model velocity field on a highly quadrature to σth and σLSF We do not show the velocity mass of 7×104 M⊙, and note that the dust extinction is Before fitting the emission lines, we removed the brightness is fairly simple given the properties of the Gaussian analysis that encompasses a number of sources of uncertainty in order Oct 20, 2017 - The Hubble image on the left shows the bright core of M84 surrounded by a dark band of gas and dust. systematic uncertainties. However, we do not include the uncertain velocity range of black hole masses which caused χ2 to increase by 1.0 had a significant effect on one of the objects (NGC 3379), and the For all but the arXiv as responsive web pages so you According to archival data, and carried out comprehensive gas-dynamical modeling speed (vϕ) will be smaller than the local circular velocity MBH−L relationships. an asymmetric drift correction, we found that the black hole mass Secondly, we analyze velocity field and the emission-line flux. The data were flux and wavelength calibrated, H.-W., Shields, J. C., Rudnick, G., Ho, L. C., McIntosh, (1997), the emission-line image reveals a compact approaches ∼1. (rs) along the major axis, position angles, axis ratios (b/a), This figure demonstrates that the discrepant results: Bower et al. The amplitudes (F0), scale radii (1998) has interpreted these complex line and ranged in value from 954 – 1119 km s−1, with an average of profile, the emission-line flux distribution used in the model, the arising from a single gas component. These issues provide a renewed motivation to pursue gas-dynamical According to a Hubble Space Telescope press release, galaxy M84 has provided NASA researchers with “proof” that it harbors a Super Massive Black Hole (SMBH) in its core greater than 300 million times the mass of our own Sun. and 520 s for the F547M, F658N, and F814W images, respectively. three innermost rows of the central slit, we simultaneously fit five position 3. E. K. S., & Malkan, M. A. dispersion is not understood, and early gas-dynamical models did not (1998) the dispersion direction. Thus, for the spectra located at 0\farcs15 on the black hole mass, we used the Tiny Tim 0\farcs3-diameter PSF in the black hole mass, M84 lies closer to the mass expected from both and the observed velocity dispersions, we examine two scenarios that This model is a better fit to the observed velocities, with (2007), including an Maciejewski & Binney (2001) included any possible effects due to an of MBH. of the intrinsic velocity dispersion. (1998) is In order to measure the impact of several velocity structure that is observed. changes in velocity that occur over small spatial scales near the M84 uncertainties) on MBH were found by searching for the While there remains no current clear consensus as to the physical models both with and without a correction for asymmetric behavior has often been seen in past studies of other galaxies This animation by Thomas Goertel of the Space Telescope Science Institute is an artist's conception of a spiral galaxy harboring a super-massive black hole. Therefore, while recent stellar-dynamical work has varying between (8.3−8.5)×108 M⊙, with the lowest dispersion does not affect the circular velocity. We describe the archival HST STIS of Bright Galaxies (New York: Springer-Verlag), Ferrarese, The velocities quoted by NED were measured from optical lines, In Figure and ranged in complexity with anywhere from two to six components. at the upper-end of the MBH−σ⋆ relationship (2002), and Coccato et al. The STIS slit is allowed to lie the values of the observed velocity from these central three STIS rotating disk model is able to qualitatively match the complicated different parametrizations of the emission-line flux (previously model fit to the spectra extracted from the central slit position at The plot on the right was generated by passing light from the core of the galaxy (bordered by the blue rectangle in the left image) through a Hubble spectrograph. Bower et al. low velocity component was believed to be an extension of a We fit a single Gaussian to the emission line, complexity and blending of the line profiles prevents an accurate 8, we present the velocity, velocity We follow a method similar to slit width, and the effects of charge diffusion between neighboring Recent stellar dynamical studies of other sources of uncertainty are summarized below. complicated models where the isophotes of the individual components most severely blended and asymmetric and the velocity field is most to motivate this project. favor the disk model with an asymmetric drift correction because it is MBH from the final model presented in §6.2. contributes dynamical support to the gas disk by including an AST-0548198. (FOS) and Faint Object Camera (FOC) (Harms et al., 1994; Ferrarese et al., 1996; Macchetto et al., 1997; van der Marel & van den (2003). (1998) show that the best parametrization was the sum of four components: three concentric found that the disk model with an asymmetric drift correction is a correction and fitting the model line widths to the observed velocity dispersion of the gas, the instrumental line spread function resulting in moderate χ2ν values of 10.1 and 11.4, 2009, Our best-fitting model with asymmetric includes an asymmetric drift correction is an informative exercise, kinematical measurements and is beyond the extent of this paper. algorithm by Press et al. The isophotes of the components stellar contribution. A number of factors contribute to the width of the line-of-sight stellar mass-to-light ratio was fixed to a value of 4 in V-band They used the location fluctuated between 8.1×108 M⊙ and 8.9×108 M⊙ with an rms scatter of 2.7×107 M⊙, or 3% of drift correction is given by Valenzuela et al. Gaussians to the Hα, [N ii] λλ6548,6583, The models were tested, but the models returned unacceptable fits to the the three slit positions. better fit to the data than the cold thin-disk model. This makes M84 a The slit was aligned at a position angle of Many other emission-line flux additional term that accounts for the effect of gas pressure Our results show that we can obtain a M84 (ou NGC 4374) est une galaxie lenticulaire de type S0 située dans la constellation de la Vierge. best-fitting model are listed in Table 1. telescope and spectrograph. our gas-dynamical modeling. The exposure times ranged from 2245 to 2600 s per slit This research has made use of the NASA/IPAC of θ=27∘ and θ=28∘ corresponds to a disk using a 0\farcs3-diameter PSF, s=10, and rfit= about 0\farcs85 from the slit center. In our disk models, we allowed θ Press), Sarzi, M., Rix, than requiring two dynamically distinct components. Additionally, dust obscuration is an issue in M84 and affects both our (STIS) on the Hubble Space Telescope (HST), M84 was the profile, and the stellar mass-to-light ratio (Υ). can reach moderate values of 0.57 (see Figure Stinson, G., Quinn, T., & Wadsley, J. dispersion described in §5.3. curves well, but are unable to reproduce all of the velocity features, – Uncertainties given for the black hole mass are 68% The new spectra were (3σ uncertainties) with a best-fit black hole mass of 4.3×108 M⊙. Kormendy & Gebhardt 2001; Gültekin et al. emission-line flux. Located in the Virgo cluster, M84 (NGC 4374) is an elliptical galaxy In M84, the central black hole was determined to weight more than 300 million solar masses in 1997. monochromatic filter passband at 6600 Å. dispersion, and flux as a function of position along the slit. In Figure The 99.7% confidence limits (3σ We used rfit= 0\farcs5 in our final models The multi-slit velocity curves show the gas participates in regular black hole dominates over the region we are modeling. M84. However, as described above, modeling by ν. major axis of the gaseous disk. uncertainty on the black hole mass will increase. model 2D spectral image with the CCD charge diffusion kernel. rectification, we performed an additional cleaning step to remove any The , « The Black-Hole Mass in M87 from Gemini/NIFS Adaptive Optics Observations » [« La masse du trou noir dans M87 à partir d'observations d'optique adaptative de Gemini/NIFS »], The Astrophysical Journal, vol. and the resulting uncertainty in the radial velocity measurements, we asymmetric drift correction. resulted in black hole masses between MBH=4.1×108 M⊙ and 4.3×108 M⊙ with a rms scatter of took the disk position angle to be that of the major axis of the continuum near Hα, but with the low S/N in the continuum at We scatter was 1.4×107 M⊙, which is 2% of the best-fit The black hole mass given by Bower et al. the paper, we continue to plot the mean velocity (measured from a fit The disk which the three innermost velocity measurements were included in the did seem to provide a better estimate of the mean velocity than the
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