Brightness Fluctuations Research Articles

The Satellite Luminosity Function of M101 into the Ultra-faint Dwarf Galaxy Regime

Abstract We have obtained deep Hubble Space Telescope (HST) imaging of four faint and ultra-faint dwarf galaxy candidates in the vicinity of M101–Dw21, Dw22, Dw23 and Dw35, originally discovered by Bennet et al. Previous distance estimates using the surface brightness fluctuation technique have suggested that these four dwarf candidates are the only remaining viable M101 satellites identified in ground-based imaging out to the virial radius of M101 (D ≈ 250 kpc). Advanced Camera for Surveys imaging of all four dwarf candidates shows no associated resolved stellar populations, indicating that they are thus background galaxies. We confirm this by generating simulated HST color–magnitude diagrams of similar brightness dwarfs at the distance of M101. Our targets would have displayed clear, resolved red giant branches with dozens of stars if they had been associated with M101. With this information, we construct a satellite luminosity function for M101, which is 90% complete to M V = −7.7 mag and 50% complete to M V = −7.4 mag, that extends into the ultra-faint dwarf galaxy regime. The M101 system is remarkably poor in satellites in comparison to the Milky Way and M31, with only eight satellites down to an absolute magnitude of M V = −7.7 mag, compared to the 14 and 26 seen in the Milky Way and M31, respectively. Further observations of Milky Way analogs are needed to understand the halo-to-halo scatter in their faint satellite systems, and connect them with expectations from cosmological simulations.

The MBHBM⋆ Project. I. Measurement of the Central Black Hole Mass in Spiral Galaxy NGC 3504 Using Molecular Gas Kinematics

Abstract We present a dynamical mass measurement of the supermassive black hole (SMBH) in the nearby double-barred spiral galaxy NGC 3504 as part of the Measuring Black Holes in below Milky Way (M ⋆) Mass Galaxies Project. Our analysis is based on Atacama Large Millimeter/submillimeter Array cycle 5 observations of the emission line. These observations probe NGC 3504's circumnuclear gas disk (CND). Our dynamical model of the CND simultaneously constrains a black hole (BH) mass of M ⊙, which is consistent with the empirical BH–galaxy scaling relations and a mass-to-light ratio in the H band of 0.44 ± 0.12 (M ⊙/ ). This measurement also relies on our new estimation of the distance to the galaxy of 32.4 ± 2.1 Mpc using the surface brightness fluctuation method, which is much further than the existing distance estimates. Additionally, our observations detect a central deficit in the integrated intensity map with a diameter of 6.3 pc at the putative position of the SMBH. However, we find that a dense gas tracer CS(5 − 4) peaks at the galaxy center, filling in the 12CO(2 − 1)-attenuated hole. Holes like this one are observed in other galaxies, and our observations suggest these may be caused by changing excitation conditions rather than a true absence of molecular gas around the nucleus.

Turbulence in stratified atmospheres: implications for the intracluster medium

ABSTRACT The gas motions in the intracluster medium (ICM) are governed by turbulence. However, since the ICM has a radial profile with the centre being denser than the outskirts, ICM turbulence is stratified. Stratified turbulence is fundamentally different from Kolmogorov (isotropic, homogeneous) turbulence; kinetic energy not only cascades from large to small scales, but it is also converted into buoyancy potential energy. To understand the density and velocity fluctuations in the ICM, we conduct high-resolution (10242 × 1536 grid points) hydrodynamical simulations of subsonic turbulence (with rms Mach number $\mathcal {M}\approx 0.25$) and different levels of stratification, quantified by the Richardson number Ri, from Ri = 0 (no stratification) to Ri = 13 (strong stratification). We quantify the density, pressure, and velocity fields for varying stratification because observational studies often use surface brightness fluctuations to infer the turbulent gas velocities of the ICM. We find that the standard deviation of the logarithmic density fluctuations (σs), where s = ln (ρ/ < ρ($z$) >), increases with Ri. For weakly stratified subsonic turbulence (Ri ≲ 10, $\mathcal {M}\lt 1$), we derive a new σs–$\mathcal {M}$–Ri relation, $\sigma _\mathrm{ s}^2=\ln (1+b^2\mathcal {M}^4+0.09\mathcal {M}^2 \mathrm{Ri} H_\mathrm{ P}/H_\mathrm{ S})$, where b = 1/3–1 is the turbulence driving parameter, and HP and HS are the pressure and entropy scale heights, respectively. We further find that the power spectrum of density fluctuations, P(ρk/ < ρ >), increases in magnitude with increasing Ri. Its slope in k-space flattens with increasing Ri before steepening again for Ri ≳ 1. In contrast to the density spectrum, the velocity power spectrum is invariant to changes in the stratification. Thus, we find that the ratio between density and velocity power spectra strongly depends on Ri, with the total power in density and velocity fluctuations described by our σs–$\mathcal {M}$–Ri relation. Pressure fluctuations, on the other hand, are independent of stratification and only depend on $\mathcal {M}$.

Source brightness fluctuation correction in Fourier-transform hyperspectral imaging of flames

Infrared emission spectra provide very useful information for the study and optimization of combustion processes. However, their characteristic brightness fluctuations (flicker) are a problem for Fourier transform spectrometers, because they introduce artifacts into the measured spectra. In this work, a method for the correction of these effects is presented which requires the acquisition of interferograms, measured in continuous (DC) mode, for both the hot combustion source and a cold reference. The method is applied to measurements in the mid-infrared of the flame of a Bunsen burner, to eliminate artifacts due to flicker, making possible quantitative studies of temperature and chemical composition.

Surface brightness fluctuation spectra to constrain stellar population properties

ABSTRACT We present a new set of surface brightness fluctuation (SBF) spectra computed with the E-MILES stellar population synthesis models. The model SBF spectra cover the range λλ1680–50 000 at moderately high resolution, all based on extensive empirical stellar libraries. The models span the metallicity range $-2.3\le \mbox{$\mbox{[M/H]}$}\le +0.26$ for a suite of intial mass function types with varying slopes. These predictions can complement and aid fluctuation magnitude studies, permitting a first-order approximation by applying filter responses to the SBF spectra to obtain spectroscopic SBF magnitudes. We provide a recipe for obtaining the latter and discuss their uncertainties and limitations. We compare our spectroscopic SBF magnitudes to photometric data of a sample of early-type galaxies. We also show that the SBF spectra can be very useful for constraining relevant stellar population parameters. We find small (<5 per cent) mass fractions of extremely metal-poor components ($\mbox{$\mbox{[M/H]}$}\lt -1$) on the top of the dominant, old, and metal-rich stellar population. These results put stringent constraints on the early stages of galaxy formation in massive elliptical galaxies. This is remarkable given the high degree of degeneracy of the standard spectral analysis to such metal-poor stellar populations in the visible and in the near-infrared. The new SBF models show great potential for exploiting ongoing surveys, particularly those based on narrow-band filters.

Direct Detection of Black Hole-driven Turbulence in the Centers of Galaxy Clusters

Abstract Supermassive black holes (SMBHs) are thought to provide energy that prevents catastrophic cooling in the centers of massive galaxies and galaxy clusters. However, it remains unclear how this “feedback” process operates. We use high-resolution optical data to study the kinematics of multiphase filamentary structures by measuring the velocity structure function (VSF) of the filaments over a wide range of scales in the centers of three nearby galaxy clusters: Perseus, A2597, and Virgo. We find that the motions of the filaments are turbulent in all three clusters studied. There is a clear correlation between features of the VSFs and the sizes of bubbles inflated by SMBH-driven jets. Our study demonstrates that SMBHs are the main driver of turbulent gas motions in the centers of relaxed galaxy clusters and suggests that this turbulence is an important channel for coupling feedback to the environment. Our measured amplitude of turbulence is in good agreement with Hitomi Doppler line broadening measurement and X-ray surface-brightness fluctuation analysis, suggesting that the motion of the cold filaments is well-coupled to that of the hot gas. The smallest scales that we probe are comparable to the mean free path in the intracluster medium. Our direct detection of turbulence on these scales provides the clearest evidence to date that isotropic viscosity is suppressed in the weakly collisional, magnetized intracluster plasma.

INT monitoring survey of Local Group dwarf galaxies: star formation history and chemical enrichment

The Local Group (LG) hosts many dwarf galaxies with diverse physical characteristics in terms of morphology, mass, star formation, and metallicity. To this end, LG can offer a unique site to tackle questions about the formation and evolution of galaxies by providing detailed information. While large telescopes are often the first choices for such studies, small telescope surveys that perform dedicated observations are still important, particularly in studying bright objects in the nearby universe. In this regard, we conducted a nine-epoch survey of 55 dwarf galaxies called the "Local Group dwarf galaxies survey" using the 2.5m Isaac Newton Telescope (INT) in the La Palma to identify Long-Period Variable (LPV) stars, namely Asymptotic Giant Branch (AGB) and Red Super Giant (RSG) stars. AGB stars formed at different times and studying their radial distribution and mass-loss rate can shed light on the structure formation in galaxies. To further investigate the evolutionary path of these galaxies, we construct their star formation history (SFH) using the LPV stars, which are at the final stages of their evolution and therefore experience brightness fluctuations on the timescales between hundred to thousand days. In this paper, we present some of the results of the Local Group dwarf galaxies survey.

Clustering of Local Group Distances: Publication Bias or Correlated Measurements? VI. Extending to Virgo Cluster Distances

Abstract We have established an internally consistent Local Group distance framework, using the Galactic Center, the Large Magellanic Cloud, and Messier 31 (M31) as important stepping stones. At greater distances, few distance benchmarks are available. As a consequence, M87 and/or Virgo cluster distances are often invoked as the next rung on the ladder to more distant objects such as the Fornax and Coma clusters. Therefore, we extensively mined the published literature for independently derived distance estimates to either M87 or the center of the Virgo cluster. Based on our newly compiled, comprehensive database of 213 such distances, published between 1929 and 2017 July, we recommend an outward extension to our distance framework, mag (D = 16.07 ± 1.03 Mpc; where the uncertainty represents the Gaussian σ of the distribution), based on a subset of recent (post-1990) M87/Virgo cluster distance measurements. The most stable distance tracers employed here were derived from analysis of both primary and secondary distance indicators. Among the former, we preferentially rely on Cepheid period–luminosity relations and red-giant-branch terminal magnitudes; our preferred secondary distance tracers are surface brightness fluctuations. Our updated distance modulus to M87 implies a slightly reduced black hole mass of (5.9 ± 0.6) × 109 M ⊙ with respect to that determined by the Event Horizon Telescope collaboration.

Revised Simulations of the Planetary Nebulae Luminosity Function

Abstract We describe a revised procedure for the numerical simulation of planetary nebulae luminosity functions (PNLFs), improving on previous work. The procedure is now based on new H-burning post-asymptotic giant branch (AGB) evolutionary tracks. For a given stellar mass, the new central stars are more luminous and evolve faster. We have slightly changed the distribution of the [O iii] 5007 intensities relative to those of and the generation of absorbing factors, while still basing their numerical modeling on empirical information extracted from studies of galactic planetary nebulae (PNs) and their central stars. We argue that the assumption of PNs being completely optically thick to H-ionizing photons leads to conflicts with observations and show that to account for optically thin PNs is necessary. We then use the new simulations to estimate a maximum final mass, clarifying its meaning, and discuss the effect of internal dust extinction as a possible way of explaining the persistent discrepancy between PNLFs and surface brightness fluctuation distances. By adjusting the range of minimum to maximum final mass, it is also possible to explain the observed variety of PNLF shapes at intermediate magnitudes. The new PN formation rates are calculated to be slightly lower than suggested by previous simulations based on older post-AGB evolutionary tracks.

The New EXor Outburst of ESO-Hα 99 Observed by Gaia ATLAS and TESS

Abstract We report photometry and spectroscopy of the outburst of the young stellar object ESO-Hα99. The outburst was first noticed in Gaia alert Gaia18dvc and later by the Asteroid Terrestrial-impact Last Alert System (ATLAS). We have established the outburst light curve with archival ATLAS orange filter photometry, Gaia data, new V-band photometry, and J, H, and K s photometry from the Infrared Imaging System (IRIS) and the United Kingdom Infrared Telescope (UKIRT). The brightness has fluctuated several times near the light curve maximum. The Transiting Exoplanet Survey Satellite (TESS) satellite observed ESO-Hα 99 with high cadence during one of these minor minima and found brightness fluctuations on timescales of days and hours. Imaging with UKIRT shows the outline of an outflow cavity, and we find one knot of emission, now named MHO 1520, on the symmetry axis of this nebula, indicating recent collimated outflow activity from ESO-Hα 99. Its pre-outburst SED shows a flat far-infrared spectrum, confirming its early evolutionary state and its similarity to other deeply embedded objects in the broader EXor class. The pre-outburst luminosity is 34 L ⊙, a much higher luminosity than typical EXors, indicating that ESO-Hα 99 may be a star of intermediate mass. Infrared and optical spectroscopy show a rich emission-line spectrum, including H i lines, strong red Ca ii emission, as well as infrared CO bandhead emission, all characteristic EXors in the broadest sense. Comparison of the present spectra with an optical spectrum obtained in 1993, presumably in the quiescent state of the object, shows that during the present outburst the continuum component of the spectrum has increased notably more than the emission lines. The Hα equivalent width during the outburst is down to one-half of its 1993 level, and shock-excited emission lines are much less prominent.

Tensions between the early and late Universe

The standard cosmological model successfully describes many observations from widely different epochs of the Universe, from primordial nucleosynthesis to the accelerating expansion of the present day. However, as the basic cosmological parameters of the model are being determined with increasing and unprecedented precision, it is not guaranteed that the same model will fit more precise observations from widely different cosmic epochs. Discrepancies developing between observations at early and late cosmological time may require an expansion of the standard model, and may lead to the discovery of new physics. The workshop "Tensions between the Early and the Late Universe" was held at the Kavli Institute for Theoretical Physics on July 15-17 2019 (More details of the workshop (including on-line presentations) are given at the website: https://www.kitp.ucsb.edu/activities/enervac-c19) to evaluate increasing evidence for these discrepancies, primarily in the value of the Hubble constant as well as ideas recently proposed to explain this tension. Multiple new observational results for the Hubble constant were presented in the time frame of the workshop using different probes: Cepheids, strong lensing time delays, tip of the red giant branch (TRGB), megamasers, Oxygen-rich Miras and surface brightness fluctuations (SBF) resulting in a set of six new ones in the last several months. Here we present the summary plot of the meeting that shows combining any three independent approaches to measure H$_0$ in the late universe yields tension with the early Universe values between 4.0$\sigma$ and 5.8$\sigma$. This shows that the discrepancy does not appear to be dependent on the use of any one method, team, or source. Theoretical ideas to explain the discrepancy focused on new physics in the decade of expansion preceding recombination as the most plausible. This is a brief summary of the workshop.

Particle acceleration in a nearby galaxy cluster pair: the role of cluster dynamics

Context. Diffuse radio emission associated with the intracluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that a fraction of the kinetic energy in mergers is channeled into nonthermal components, such as turbulence, cosmic rays, and magnetic fields, which may lead to the formation of giant synchrotron sources in the ICM. Aims. Studying merging galaxy clusters in different evolutionary phases is fundamental for understanding the origin of radio emission in the ICM. Methods. We observed the nearby galaxy cluster pair RXC J1825.3+3026 (z ∼ 0.065) and CIZA J1824.1+3029 (z ∼ 0.071) at 120 − 168 MHz with the LOw Frequency ARray (LOFAR) and made use of a deep (240 ks) XMM-Newton dataset to study the nonthermal and thermal properties of the system. RXC J1825.3+3026 is in a complex dynamical state, with a primary ongoing merger in the E-W direction and a secondary later stage merger with a group of galaxies in the SW, while CIZA J1824.1+3029 is dynamically relaxed. These two clusters are in a pre-merger phase. Results. We report the discovery of a Mpc-scale radio halo with a low surface brightness extension in RXC J1825.3+3026 that follows the X-ray emission from the cluster center to the remnant of a galaxy group in the SW. This is among the least massive systems and the faintest giant radio halo known to date. In contrast to this, no diffuse radio emission is observed in CIZA J1824.1+3029, nor in the region between the pre-merger cluster pair. The power spectra of the X-ray surface brightness fluctuations of RXC J1825.3+3026 and CIZA J1824.1+3029 are in agreement with the findings for clusters exhibiting a radio halo and clusters where no radio emission has been detected, respectively. Conclusions. We provide quantitative support to the idea that cluster mergers play a crucial role in the generation of nonthermal components in the ICM.

Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: Calibration and Methodology

Abstract We explore the use of ground-based surface brightness fluctuation (SBF) measurements to constrain distances to nearby dwarf galaxies. Using archival CFHT Megacam imaging data for a sample of 28 nearby dwarfs, we demonstrate that reliable SBF measurements and distances accurate to 15% are possible even for very low surface brightness (μ 0i > 24 mag arcsec−2) galaxies with modest, ∼hour-long exposures with CFHT. Combining our sample with a recent sample of six dwarfs with SBF measured with Hubble Space Telescope (HST) from the literature, we provide the most robust empirical SBF calibration to date for the blue colors expected for these low-mass systems. Our calibration is credible over the color range 0.3 ≲ g − i ≲ 0.8 mag. It is also the first SBF calibration tied completely to tip of the red giant branch (TRGB) distances as each galaxy in the sample has a literature TRGB distance. We find that even though the intrinsic scatter in SBF increases for blue galaxies, the rms scatter in the calibration is still ≲0.3 mag. We verify our measurements by comparing with HST SBF measurements and detailed image simulations. We argue that ground-based SBF is a very useful tool for characterizing dwarf satellite systems and field dwarfs in the nearby, D ≲ 20 Mpc universe.

PHOTOMETRIC RESEARCH OF SEYFERT GALAXIES MRK 766, MRK 6, MRK 1040, MRK 1513

The paper presents the results of the photometric observations of the Seyfert galaxies from theMarkarian list: MRK 766, MRK 6, MRK 1040, MRK 1513. The observations were carried out on “the Eastern“ 1-meter telescope, located at the Tien-Shan Astronomical Observatory of the Fesenkov Astrophysical Institute. Theobservational data were processed using the MaximDL6 software package. The brightness was estimated bydifferential photometry, using standard stars in the vicinity of galaxies. This paper presents the light curves of thegalaxies: Mrk 766, Mrk 6, Mrk 1040, Mrk 1513. It has been noted, that in Mrk 766, there is a tendency to a gradualweakening of the brightness in the three filters. Photometric changes of the galaxy Mrk 6 during 2016-2019 occurredsynchronously in all three filters. The weakening of its brightness began in 2017and by 2019 it reached ~ 0m.9.During the investigation period, irregular brightness fluctuations were registered in galaxies Mrk 1040 and Mrk 1513with amplitudes of ~ 1m 0 and 0m.8, respectively.

Using Surface Brightness Fluctuations to Study nearby Satellite Galaxy Systems: The Complete Satellite System of M101

Abstract We use surface brightness fluctuation (SBF) measurements to constrain the distance to low surface brightness (LSB) dwarfs in the vicinity of M101. Recent work has discovered many LSB candidate satellite companions of M101. However, without accurate distances, it is problematic to identify these dwarfs as physical satellites of M101. We use CFHT Legacy Survey data to measure the SBF signal for 43 candidate dwarfs. The data are deep enough that we constrain 33 of these to be unassociated background galaxies by their lack of SBF. We measure high S/N SBF signals for two of the candidate dwarfs, which are consistent with being at the distance of M101. The remaining candidates are too LSB and/or small for their distances to be constrained. Still, by comparison with Local Group dwarfs, we argue that the M101 satellite system is likely now complete down to stellar masses of ∼5 × 105 M ⊙. We also provide a new SBF distance for the nearby dwarf UGC 8882, which suggests that it might be a physical satellite of M101; however, further study is merited. By constraining the distances to a majority of the candidates using only archival data, our work demonstrates the usefulness of SBF for nearby LSB galaxies and for studying the satellite systems of nearby massive galaxies.

Extreme-ultraviolet and X-Ray Emission of Turbulent Solar Flare Loops

Abstract Turbulence has been observed in flare loops and is believed to be crucial for the acceleration of particles and in the emission of X-ray photons in flares, but how the turbulence is produced is still an open question. A scenario proposed by Fang et al. suggests that fast evaporation flows from flare loop footpoints can produce turbulence in the looptop via the Kelvin–Helmholtz instability (KHI). We revisit and improve on this scenario and study how the KHI turbulence influences extreme-ultraviolet (EUV) and X-ray emission. A 2.5D numerical simulation is performed in which we incorporate the penetration of high-energy electrons as a spatio-temporal dependent trigger for chromospheric evaporation flows. EUV, soft X-ray (SXR), and hard X-ray (HXR) emission are synthesized based on the evolving plasma parameters and given energetic electron spectra. KHI turbulence leads to clear brightness fluctuations in the EUV, SXR, and HXR emission, with the SXR light curve demonstrating a clear quasi-periodic pulsation (QPP) with period of 26 s. This QPP derives from a locally trapped, fast standing wave that resonates in between KHI vortices. The spectral profile of the Fe xxi 1354 line is also synthesized and found to be broadened due to the turbulent motion of plasma. HXR tends to mimic the variation of SXR flux and the footpoint HXR spectrum is flatter than the looptop HXR spectrum.

Surface Brightness Fluctuations for constraining the chemical enrichment of massive galaxies

AbstractBased on very deep photometry, Surface Brightness Fluctuations (SBF) have been traditionally used to determine galaxy distances. We have recently computed SBF spectra of stellar populations at moderately high resolution, which are fully based on empirical stars. We show that the SBF spectra provide an unprecedented potential for stellar population studies that, so far, have been tackled on the basis of the mean fluxes. We find that the SBFs are able to unveil metal-poor stellar components at the one percent level, which are not possible to disentangle with the standard analysis. As these metal-poor components correspond to the first stages of the chemical enrichment, the SBF analysis provides stringent constrains on the quenching epoch.

Constraining Gas Motions in the Intra-Cluster Medium

The detailed velocity structure of the diffuse X-ray emitting intra-cluster medium (ICM) remains one of the last missing key ingredients in understanding the microphysical properties of these hot baryons and constraining our models of the growth and evolution of structure on the largest scales in the Universe. Direct measurements of the gas velocities from the widths and shifts of X-ray emission lines were recently provided for the central region of the Perseus Cluster of galaxies by $Hitomi$, and upcoming high-resolution X-ray microcalorimeters onboard $XRISM$ and $Athena$ are expected to extend these studies to many more systems. In the mean time, several other direct and indirect methods have been proposed for estimating the velocity structure in the ICM, ranging from resonant scattering to X-ray surface brightness fluctuation analysis, the kinematic Sunyaev-Zeldovich effect, or using optical line emitting nebulae in the brightest cluster galaxies as tracers of the motions of the ambient plasma. Here, we review and compare the existing estimates of the velocities of the hot baryons, as well as the various overlapping physical processes that drive motions in the ICM, and discuss the implications of these measurements for constraining the viscosity and identifying the source of turbulence in clusters of galaxies.

The Breakthrough Listen Search for Intelligent Life: Searching Boyajian's Star for Laser Line Emission

Boyajian's Star (KIC 8462852) has received significant attention, due to its unusual periodic brightness fluctuations detected by the Kepler spacecraft and subsequent ground-based observations. Possible explanations for the dips in the photometric measurements include interstellar or circumstellar dust, and it has been speculated that an artificial megastructure could be responsible. We analyze 177 high-resolution spectra of Boyajian’s Star in an effort to detect potential laser signals from extraterrestrial civilizations. The spectra were obtained by the Lick Observatory’s Automated Planet Finder (APF) telescope as part of the Breakthrough Listen Project, and cover the wavelength range of visible light from 374 to 970 nm. We calculate that the APF would be capable of detecting lasers of power greater than approximately 24 MW at the distance of Boyajian’s Star, d = 1470 ly. The top candidates from the analysis can all be explained as either cosmic-ray hits, stellar emission lines or atmospheric airglow emission lines.

Turbulence in the intracluster medium: simulations, observables, and thermodynamics

We conduct two kinds of homogeneous isotropic turbulence simulations relevant for the intracluster medium (ICM): (i) pure turbulence runs without radiative cooling; (ii) turbulent heating$+$radiative cooling runs with global thermal balance. For pure turbulence runs in the subsonic regime, the rms density and surface brightness (SB) fluctuations vary as the square of the rms Mach number ($\mathcal{M}_{\text{rms}}$). However, with thermal balance, the density and SB fluctuations $(\delta SB/SB)$ are much larger. These scalings have implications for translating SB fluctuations into a turbulent velocity, particularly for cool cores. For thermal balance runs with large (cluster core) scale driving, both the hot and cold phases of the gas are supersonic. For small scale (one order of magnitude smaller than the cluster core) driving, multiphase gas forms on a much longer timescale but $\mathcal{M}_{\text{rms}}$ is smaller. Both small and large scale driving runs have velocities larger than the Hitomi results from the Perseus cluster. Thus turbulent heating as the dominant heating source in cool cluster cores is ruled out if multiphase gas is assumed to condense out from the ICM. Next we perform thermal balance runs in which we partition the input energy into thermal and turbulent parts and tune their relative magnitudes. The contribution of turbulent heating has to be $\lesssim 10\%$ in order for turbulence velocities to match Hitomi observations. If the dominant source of multiphase gas is not cooling from the ICM (but say uplift from the central galaxy), the importance of turbulent heating cannot be excluded.