https://www.irynabutsky.me/research daily 0.75 2026-04-02 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695325543931-FL7BGQQ5EXEW5YKYU1FD/Screen+Shot+2017-10-08+at+4.10.40+PM.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695325602544-HQ0VGS2J4RK2ST9QPFE4/baryons.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695325722641-UIENFKWURP2GK0BI4RXF/Milky_Way_RM.PNG Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695326123454-OYXS6WUBTPP0D1TUJU52/multipanel_metallicity_ion.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695326530076-ON61ULKM3BGYYJM2KTZJ/merged_pdf_tctf_1.0_cr_1.0.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695326615206-1TDXXGUWXPVMOFH3NTWD/multipanel_plot_romulusC_3035.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1695329065944-ZATOMWBWXUWJAFNXN5WY/sightline_data_P0_agncr_0018.jpg Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1664490688919-DJKFV3ROD8IWQ8E86060/Screen+Shot+2022-09-29+at+15.31.01.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1696877101288-2H0C8KV6Q0IUVEZ3KQ6E/scattering_diagram_4.jpg Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/631428cf-eaa8-4c95-b8e3-11e07f27dde8/Screenshot+2026-04-02+at+14.27.51.png Research https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510038583299-466W5G2SEJ9310A1C5FG/Screen+Shot+2017-10-08+at+4.08.16+PM.png Research Figure 1: The corrugation modes with radial nodes n = 0, 1, 2 for accretion disks around black holes with spin a/M = 0.001, 0.01, 0.1, 0.5, 0.9 . https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510449073750-PD095L2U4GLCFYC13XZ6/ldimage.png Research Figure 2: An example of corrugation modes in accretion disk images as a function of the phase of the perturbation. Moving clockwise from the top left corner, the oscillation phase increases by π/2. The color represents the redshift, while the brightness represents the intensity. This is a representation of an accretion disk for a black hole with spin a/M = 0.001, μo = 0.5, and an arbitrarily chosen r=20M. These images were created assuming a limb brightening law, f(μem) = log(1 + 1/μem), for the angular emissivity. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510452763617-6MFJ0Q3IHP9AI4PYBSKN/Screen+Shot+2017-11-11+at+6.12.09+PM.png Research Figure 3: The first row shows the unperturbed broadened line spectra. The remaining rows show the spectral variation (the difference in intensity from the average spectra) as a function of oscillation phase and observed frequency ratio for the precession of a tilted disc, and the n = 0, n = 1, and n = 2 corrugation modes. Here we assume limb darkening angular emissivity for a black hole with spin a = 0.01 and inclinations µo = cos θ = 0.1, 0.5, and 0.7. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510618742111-YCI7X5HE14YLJKLO61YD/image-asset.png Research Figure 1: Face-on (upper panels) and edge-on (lower panels) views of four selected “test” galaxies from the NIHAO simulation suite arranged from left to right by increasing mass. Galaxies have been processed through the Monte Carlo radiative transfer code sunrise. Images are 50 kpc on a side.. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510984602007-086E81TFTBW9QU37VHVS/Screen+Shot+2017-11-13+at+4.47.25+PM.png Research Figure 2: Ratio of minor-to-major axes (c/a) as a function of radius for high mass (top) and intermediate mass (bottom) galaxies. DM-only simulations are depicted in black, while hydro (NIHAO) simulations are depicted in red. The shaded region represents the 1σ scatter from galaxy to galaxy in the respective mass bins. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510984304275-57MACKWKC6B82PYY7I9I/Screen+Shot+2017-11-17+at+9.51.13+PM.png Research Figure 3: The dark matter particles velocity distribution for a collection of intermediate mass galaxies. The top panels show the global velocity distribution, while the bottom panels show local measurements taken at the solar position ( 7 kpc < r < 9 kpc). DM-only simulations are depicted in black, while hydro (NIHAO) simulations are depicted in red. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510467939918-Y40CO7YIQG0IO1LAW4A2/g80_lr.png Research Figure 1: The edge-on (left) and face-on (right) projections of the magnetic field strength (top), density (center), and temperature (bottom) of galaxy g80LR at t = 2.1 Gyr in 30 kpc boxes. Magnetic field streamlines are plotted in black over the image of the magnetic field strength. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510468728011-K89NINDEYRVM7UHYX0H0/g80_486_n128_T13000.png Research Figure 3: All-sky RM map for the g80LR run at ∼ 2.4Gyr with Tthres = 13,000K and an origin 8 kpc away from the center of the galaxy. The angular power spectrum of this map is shown in Figure 7. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1554356156356-11JGE27QGHU46I7JG1CY/multipanel_plot_romulusC_3035.png Research Figure 1: The RomulusC cluster simulation at a redshift of 0.31. The top row shows quantities of the cluster that are readily available simulations: the gas density, temperature, and metallicity. However these properties cannot be directly observed and must be inferred from careful modeling. The bottom row shows quantities that can be directly observed: the X-ray emission and the O VI and H I absorption column density. X-ray emission traces the hot, dense intracluster medium, which has a dramatically different structure from the diffuse, cool-warm gas traced by absorption in the UV. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1596405948741-MXIIZIE3UEN0NXDSYD72/density_multipanel_slice_isocool_tctf_0.3_beta_100.0_cr_compare_40.png Research Figure 1: 2D slice of the 3D density in simulations with different ratios of cosmic ray pressure (increasing left to right). In all simulations, cold, dense gas forms through thermal instability. With increased cosmic ray pressure, the cold gas clouds become larger and less dense. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1517339550243-7FYJ07RK3OE2I1YGBRZ0/outflow.png Research Figure 1: Cosmic ray transport relative to the thermal gas can drive strong galactic winds (top panel). Cosmic ray pressure provides support to the thermal gas (bottom panel), lifting it out of the galactic potential well. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1521225526922-15MB7AOM3RYBACNPAIQ6/multipanel_metallicity_ion.png Research Figure 2: Cosmic ray-driven winds expel metal-rich gas into the CGM (top panel). The presence of cosmic rays in the CGM affects the temperature and ionization structure of the diffuse gas. However, that structure is sensitive to the choice of cosmic ray transport. Therefore, careful parameter studies are necessary before simulations with cosmic ray feedback hold predictive power. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/52346c10-a4c3-4f5f-a1ed-6a1e36cbc21a/scattering_diagram_4.jpg Research - Make it stand out Figure 1: A cartoon depiction of traditional, continuous cosmic-ray scattering models (top) and our proposed patchy scattering model (bottom). Any successful model must reproduce the observed power-law relationship between the average cosmic-ray scattering rate and cosmic-ray energy (/rigidity). In both cases, cosmic rays are accelerated by galactic supernovae and travel around tangled magnetic field lines before being detected at (or near) the Earth. Magnetic fluctuations the size of a cosmic-ray gyroradius perturb/”scatter” the cosmic-ray pitch angle, Traditional models assume that this scattering is “continuous” throughout a homogenous ISM. In order to produce the observed dependence between cosmic-ray scattering rate and energy, this assumption imposes a specific power-law of magnetic fluctuations that has not yet been explained theoretically. We propose an alternative, intermittent, model of cosmic-ray scattering in which cosmic rays “free stream” near the speed of light most of the time, and are strongly scattered in discrete “patches”. In this model, smaller patches scatter lower energy cosmic rays and larger patches scatter both, lower and higher energy cosmic rays. Therefore, we can avoid the pitfalls of continuous scattering theories with the right distribution of scattering patch sizes. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/6d9dc55d-8a74-4270-9e1d-a4f2d7addb4c/fvol_size_3.jpg Research - Make it stand out Figure 2. The minor axis and volume-filling factor required of the patchy scattering model. The black shaded regions shows a hypothetical intermittent scattering model that would reproduce all of the required observations. A natural category of candidates for the scattering structures suggested above is intermittent turbulent structure. The required volume-filling factors are intriguingly similar to some estimates for the volume-filling factors of “tiny-scale atomic structures” and “extreme scattering events”. Note these are categories of ISM structures classified by their effects on radio waves: physical explanations for such structures range widely, but often invoke intermittent turbulent structures, which we discuss below. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/4c66a240-91ac-474b-b29c-def6f5dcf389/Figure5_cropped.png Research Figure 1: Example of kinematic alignment from the COS-Halos survey. Figure is taken from Tumlinson, Peeples, Werk 2017. HI, SiII, SiIII, SiIV, and OVI all trace a wide range of gas densities and temperatures, and yet their absorption features all have the same line-of-sight velocity. This hints at some physical relationship between the different gas phases. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/7008170d-f7e9-4caf-926a-f580a0740816/multipanel_003195_sim_z.png Research - Make it stand out Figure 2: Snapshots of the CGM of the two case-study galaxies. The different panels show the density, temperature, and line-of-sight velocity in the inner CGM supported by thermal pressure (top) and cosmic-ray pressure (bottom) at redshift 0.25. The cosmic-ray-pressure-supported CGM builds up a reservoir of cool, low-density gas, which has qualitatively different velocities from the small, dense cold clouds in the thermal-pressure-supported CGM. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/fb3dc6ae-6cb5-4737-bce1-3796f6475d8e/sightline_data_P0_agncr_0028.png Research - Make it stand out Figure 3: An example of a synthetic spectrum generated from a simulated cosmic-ray-pressure-supported CGM. The top panel shows the line-of-sight velocities of Si III and O VI. The remaining panels show the physical properties along the line of sight of the particles that contributed to generating the spectra. This specific plot is an example of kinematic alignment due to a large, rotating cool gas cloud in the inner CGM enveloped by a warmer, co-rotating medium. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/74c39dd4-feb8-4058-af8f-51561877cf86/cosmic+ray+effective+transport2.001.jpg Research - Make it stand out Figure 1: Cosmic-ray transport is severely under-constrained. This toy plot highlights the fact that the existing observations only constrain cosmic-ray transport in the ~local ISM. It is not clear how to extrapolate these transport rates to other environments, for example, the ISM of other galaxies or the CGM. There is a wide range of existing cosmic-ray transport models that can match all of the relevant observations in the local ISM that then diverge by orders of magnitude in their predictions for the cosmic-ray transport rate in the CGM. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/fc958526-d390-4857-b98d-aa0f24c1103f/Screen+Shot+2022-09-29+at+13.58.28.png Research Figure 1: A (simplified) schematic of cosmic rays in the CGM. Galactic supernovae inject roughly 10% of their energy as cosmic-ray energy. Those cosmic rays move away from their injection site along tangled magnetic fields, creating a cosmic-ray pressure gradient that helps maintain hydrostatic equilibrium. This cosmic-ray pressure may be a significant, or even the dominant pressure source in the CGM around L* galaxies, however, the quantitative details (e.g., the exact cosmic-ray pressure or its radial extent) are sensitive to models of cosmic-ray transport, which remain unconstrained. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1fc1d7a6-6865-4207-89b3-303f51a2407d/cosmic+ray+effective+transport2.001.jpg Research - Make it stand out Figure 3: The first constraints to the cosmic-ray transport rate in the CGM. Using the analytic model in Butsky et al. 2023, the scattered points show the lower limit of the effective cosmic-ray transport rate for the COS-Halos galaxy sample (Werk at al. 2013). The clear increase in the effective cosmic-ray transport rate at large galactocentric distances rules out models of cosmic-ray transport in which the transport rate does not increase in the CGM. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/631428cf-eaa8-4c95-b8e3-11e07f27dde8/Screenshot+2026-04-02+at+14.27.51.png Research - Make it stand out Figure 1: A schematic of the CGSM two-fluid framework. Each simulation cell simultaneously evolves a standard "hot" fluid and a second, unresolved "cold" fluid representing an ensemble of tiny cold cloudlets. The two fluids interact by exchanging mass, momentum, and energy according to prescriptions informed by high-resolution simulations of thermal instability and cloud crushing. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/b89e8cc8-f448-4211-9fd1-5440cb258b4d/Screenshot+2026-04-02+at+14.29.00.png Research - Make it stand out Figure 2: A comparison of cold gas distributions in a 16×16 kpc patch of CGM gas across four simulations. From left to right: a high-resolution traditional simulation (correctly producing a uniform mist of ~10 pc cloudlets), a low-resolution traditional simulation (artificially concentrating cold gas into a few kpc-scale blobs), the high-resolution result binned down to low resolution (showing what the correct answer looks like at that scale), and a low-resolution CGSM simulation (successfully recovering the smooth, realistic cold gas distribution without directly resolving the cloudlets). https://www.irynabutsky.me/about daily 1.0 2026-04-02 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/2a3f734a-5530-4e00-94a3-3dd54d41e3d5/IMG_0887.jpg About https://www.irynabutsky.me/pagecv daily 0.75 2022-10-26 https://www.irynabutsky.me/personal daily 0.75 2026-04-02 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775162670570-5EWICR3ZZ9PENGKYPQQ9/I%2BDBW-1070+%281%29.jpg Personal https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1759519737010-7PJ850SE6MWXFVND1XM8/IMG_0505.jpg Personal https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1666805119047-797MZWHZP02IG95DX8VH/IMG_1313.jpeg Personal https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1666805443420-NV99EKRMZQYBLD19A67A/IMG_3657.jpeg Personal https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1544052493567-MFYZDTJ5S3NR715ZBDCW/44425915_2005819629531625_4828151529413913005_n.jpg Personal https://www.irynabutsky.me/simulating-crs daily 0.75 2018-02-05 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1510462761987-C7GUKA0PZC0UT22WT8KX/background_frame.010.png Simulating Cosmic Rays https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1517508927914-HXC1FC3Z34ALD1WKIZMH/BW_shocktube.png Simulating Cosmic Rays Figure 1: We test the advection properties of our cosmic ray fluid with the modified Brio-Wu shock-tube https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1517340067987-NOZHO1Q6B8W59TFFFJHF/pfrommer.png Simulating Cosmic Rays Figure 2: An initial wedge of cosmic ray energy density diffuses around circular magnetic field lines over time. https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1517340410392-SMLX6AS5TO3MOE4XT94B/streaming.png Simulating Cosmic Rays Figure 3: Although no analytic solution exists for cosmic ray streaming, we compare the evolution of an initial Gaussian overdensity of cosmic ray energy under diffusion and streaming. https://www.irynabutsky.me/cr-cgm daily 0.75 2022-09-29 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1664490688919-DJKFV3ROD8IWQ8E86060/Screen+Shot+2022-09-29+at+15.31.01.png Cosmic Rays and the CGM https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/fc958526-d390-4857-b98d-aa0f24c1103f/Screen+Shot+2022-09-29+at+13.58.28.png Cosmic Rays and the CGM Figure 1: A (simplified) schematic of cosmic rays in the CGM. Galactic supernovae inject roughly 10% of their energy as cosmic-ray energy. Those cosmic rays move away from their injection site along tangled magnetic fields, creating a cosmic-ray pressure gradient that helps maintain hydrostatic equilibrium. This cosmic-ray pressure may be a significant, or even the dominant pressure source in the CGM around L* galaxies, however, the quantitative details (e.g., the exact cosmic-ray pressure or its radial extent) are sensitive to models of cosmic-ray transport, which remain unconstrained. https://www.irynabutsky.me/movies daily 0.75 2024-03-19 https://www.irynabutsky.me/data daily 0.75 2021-06-25 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1624580274439-WHRCKWUU7SKWA09BLU54/sightline_data_P0_agncr_0028.png Data - Synthetic spectroscopy Download synthetic spectra profiles for all sightlines from Butsky et al. 2021 https://www.irynabutsky.me/cv-copy daily 0.75 2022-10-26 https://www.irynabutsky.me/tinytests daily 0.75 2025-04-25 https://www.irynabutsky.me/personal-1 daily 0.75 2026-04-02 https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098185321-T94NJL8XMSFN3K5NTKKN/IMG_1250.jpeg Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098173711-SQNHF59KI6XNCDZCWHH0/IMG_1292.jpeg Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098218738-Q9AQ5IHT77GUSWT9YQ0O/IMG_1872.jpeg Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098196052-IMUDIBXXNP3XH76U29X0/IMG_1231.jpeg Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098192562-GHY10U23GL5IZ9LFORCH/IMG_1307.jpeg Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098211208-SYIAC4O4PZ0A8B0DU351/IMG_8552.JPG Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098221404-PKKYWEQBYRXVXRQ5MGP4/IMG_8553.JPG Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098172614-HV5SWJDEHNY0R9B3VJ6W/IMG_1251.jpeg Photography https://images.squarespace-cdn.com/content/v1/59daaaf0a8b2b06fbe11f47e/1775098180967-20KECZQA9TFSB5QOY7K7/IMG_1248.jpeg Photography https://www.irynabutsky.me/new-products daily 0.75 2026-03-27